Universally Recognized Principles via Advocatetanmoy Law Library

Global Forensic Science Test 1st Set via Advocatetanmoy Law Library

1- Dying declaration is to be preferably recorded by

(A) Doctor

(B) Police

(C) Magistrate

(D) Jury Member

Answer: (C)

2. Murder cases are tried in the following courts

(A) Chief Judicial Magistrate’s Court

(B) 1st Class Metropolitan Magistrate’s Court

(C) Sessions Court

(D) High Court

Answer: (C)

3. Police inquest is conducted under section

(A) 174 CrPC

(B) 174 IPC

(C) 176 CrPC

(D) 176 IPC

Answer: (A)

4. Assertion (A): Blood stains on cloth should be collected after drying in shade under room heater.

Reason (R): It causes disintegration of blood stains.

(A) Both (A) and (R) are correct.

(B) Both (A) and (R) are incorrect.

(C) (A) is correct, but (R) is incorrect.

(D) (A) is incorrect, but (R) is correct.

Answer: (D)

5. Preservation of footprint on snow can be done by

(A) Plaster of Paris Cast

(B) Sulphur Casting

(C) Tracing

(D) Wax Casting

Answer: (B)

6. Light that has all its waves pulsating in unison is called

(A) Maser

(B) Laser

(C) Monochromatic light

(D) Polychromatic light

Answer: (B)

7. Hollow Cathode Lamp (HCL) is used in the following:

(A) Atomic Absorption Spectrometer

(B) Atomic Emission Spectrometer

(C) Infra Red Spectrometer

(D) X-ray Fluorescence Spectrometer

Answer: (A)

8. Deviations from Beer’s Law fall into which categories?

(A) Real

(B) Instrumental

(C) Chemical

(D) All of the above

Answer: (D)

9. One of the following is not the component of Kastle-Meyer Test

(A) Phenolphthalein

(B) Glacial Acetic Acid

(C) Zinc dust

(D) Potassium Hydroxide

Answer: (B)

10. Confirmation of menstrual blood stain is done by the following method:

(A) Isoenzyme marker

(B) Fibrin Degradation Product (FDP)

(C) Protein Marker

(D) Restriction enzymes

Answer: (B)

11. The complementary base pairs among four nucleotides (A, T, G, C) are as

(A) A= G and T = C

(B) A = C and G = T

(C) A = T and G = C

(D) All of the above

Answer: (C)

12. Seminal fluid is a gelatinous material produced in males by seminal vesicles, prostate and

(A) Adrenal gland

(B) Pituitary gland

(C) Cowper’s gland

(D) Thyroid gland

Answer: (C)

13. The level of toxicity of Datura plant on the basis of increasing level is

(A) Root, Seeds, Fruit, Leaf

(B) Leaf, Root, Fruit, Seeds

(C) Fruit, Root, Seeds, Leaf

(D) Seeds, Leaf, Root, Fruit

Answer: (B)

14. Sodium and Potassium hydroxides are strongly corrosive due towww.netugc.com

(A) Their solvent action on protein material

(B) Their saponifying action on the lipids

(C) Their ability to extract water from the tissues

(D) All of above

Answer: (D)

15. In case of carbon monoxide poisoning which preservative is recommended for the preservation of blood samples

(A) Sodium Chloride

(B) Sodium Fluoride

(C) Sodium Carbonate

(D) No preservative

Answer: (D)

16. Free sulphuric acid is rarely found in stomach contents in acid poisoning cases because

(A) It may be vomited out

(B) May be neutralised by alkalies given as antidotes

(C) May combine chemically with the tissue with which it comes in contact

(D) All the above

Answer: (D)

17. Arrange the following firearms in the proper chronological order:

(i) Flint lock

(ii) Wheel lock

(iii) Match lock

(iv) Percussion cap lock

Codes:

(A) (ii) (iii) (iv) (i)

(B) (iii) (i) (ii) (iv)

(C) (iv) (ii) (i) (iii)

(D) (i) (iv) (iii) (ii)

Answer: (B)

18. The Indian Arms Act was enforced in

(A) 1955

(B) 1959

(C) 1961

(D) 1964

Answer: (B)

19. The bore of the 12 bore gun is

(A) 0.723″

(B) 0.727″

(C) 0.729″

(D) 0.731″

Answer: (C)

21. The diameter of SG pellet in 12 bore gun cartridge is

(A) 8.43 mm

(B) 7.77 mm

(C) 6.83 mm

(D) 5.16 mm

Answer: (A)

22. Faeces stains are identified from odour, presence of indigested matter, vegetable fibres and

(A) Stercobilin

(B) Dark brown crystals of choline iodide

(C) Rhombic crystals

(D) All of the above

Answer: (A)

23. Assertion (A): Hair has paramount importance to establish the link between suspect and victim and linking both with the scene of occurrence.

Reason (R): As per Locards principle of exchange.

Codes:

(A) (A) is correct, but (R) is incorrect.

(B) Both (A) and (R) are incorrect.

(C) (R) is correct, but (A) is incorrect.

(D) Both (A) and (R) are correct.

Answer: (D)

24. The direction of a wound can be ascertained from which of the following injuries:

(A) Chop wound

(B) Contusion

(C) Incised wound

(D) Laceration

Answer: (C)

25. Lanugo hairs are

(A) Pigmented

(B) Thin and soft

(C) Medullated

(D) Scale pattern is complex

Answer: (B)

26. The following method is used for determining the age of an ink by tracking the degradation of certain dyes.

(A) Thin layer chromatography (TLC)

(B) Gas chromatography (GC)

(C) Laser desorption mass spectrometry (LDMS)

(D) High Performance Liquid Chromatography (HPLC)

Answer: (C)

27. LSD is derived from which of the following plant?

(A) Cannabis sp.

(B) Papaver Somniferum

(C) Erthroxylum sp.

(D) Clavicepspurpurea

Answer: (D)

28. Linseed, Safflower and Cottonseed are used for

(A) Paint pigments

(B) Paint oils

(C) Paint solvents

(D) Paint binders

Answer: (B)

29. Assertion (A): As the rhodamine ‘B’ in ballpoint pen ink degrades, it loses the ethyl groups.

Reason (R): The ethyl groups are replaced by hydrogen atoms.

Codes:

(A) Both (A) and (R) are true.

(B) Both (A) and (R) are false.

(C) (A) is true, but (R) is false.

(D) (A) is false, but (R) is true.

Answer: (A)

30. For hardening of plaster of paris cast of foot prints, following substance is added:

(A) Sodium chloride

(B) Sodium carbonate

(C) Talcum powder

(D) Sodium sulphate

Answer: (B)

31. When the temperature of a liquid is raised

(A) Its refractive index increases

(B) Its refractive index decreases

(C) Its refractive index disappears

(D) Its refractive index doesn’t change

Answer: (B)

32. The skid marks on the road in a vehicular accident may give an indication of

(A) Make of the vehicle

(B) Speed of the vehicle

(C) Weight of the vehicle

(D) Height of the vehicle

Answer: (B)

33. Chemical etching is a method for restoration of erased marks on

(A) Wood

(B) Leather

(C) Metal

(D) Plastic

Answer: (C)

34. Scales are found on the following fibre:

(A) Wool

(B) Cotton

(C) Linen

(D) Silk

Answer: (A)

35. Fractures due to heat are

(A) Radial

(B) Spiral

(C) Hackle marks

(D) Wavy

Answer: (D)

36. Which of the following type of abrasions are associated in sexual assault over the thigh of a woman?

(A) Graze

(B) Imprint

(C) Pressure

(D) Scratch

Answer: (D)

37. The chromosome pattern in Turner’s syndrome is

(A) XXY

(B) XO

(C) XXX

(D) XYY

Answer: (B)

38. Cusp of Carabelli is found on

(A) Incisors Central

(B) Canines

(C) Bicuspids

(D) Tricuspids

Answer: (D)www.netugc.com

39. ABO grouping is based on

(A) Red cell surface antigen

(B) Plasma proteins

(C) Red cell enzyme

(D) Nuclear chromatin

Answer: (A)

40. The total number of bones in the human skeleton in an adult is

(A) 208

(B) 308

(C) 408

(D) 508

Answer: (A)

41. In handwriting comparison the crossing in ‘t’ and the dots in ‘i’ and ‘j’ are known as

(A) Connective signs

(B) Diacrytic signs

(C) Loop signs

(D) Shoulder signs

Answer: (D)

42. Which of the following disease affects handwriting?

(A) Chronic Leukaemia

(B) Chronic Malaria

(C) Parkinsonism

(D) Thalassemia

Answer: (C)

43. The following is a sign of forgery:

(A) Retouching

(B) Connecting strokes

(C) Pen lifts

(D) All of the above

Answer: (D)

44.The most suitable solvent system for thin layer chromatography/paper chromatography of inks is

(A) N-butanol: pyridine: water (3: 1: 1.5)

(B) Amyl alcohol: acetic acid: chloroform (6: 1: 2)

(C) Ethanol: Acetone: acetic acid (4: 1: 5)

(D) Amyl alcohol: acetic acid: pyridine (6: 1: 2)

Answer: (A)

45. The following is the most acceptable method for revealing indented writing:

(A) Oblique lighting

(B) Intense lighting

(C) Rubbing with a pencil lead

(D) ESDA

Answer: (D)

46. Cadaveric spasm indicates

(A) Suicide

(B) Homicide

(C) Natural death

(D) Last act of a person before death

Answer: (D)

47. The sequence of post-mortem changes in a cadaver includes

(A) Rigor mortis, primary flaccidity, secondary flaccidity, marbling

(B) Primary flaccidity, secondary flaccidity, rigor mortis, marbling

(C) Marbling, secondary flaccidity, primary flaccidity, rigor mortis

(D) Primary flaccidity, rigor mortis, secondary flaccidity, marbling

Answer: (B)

48. “Taches Noire Scleroitiques” is a post-mortem feature seen in

(A) Eyes

(B) Nostrils

(C) Ears

(D) Mouth

Answer: (A)

49. The following are examples of unnatural sexual offences

(i) Sodomy

(ii) Incest

(iii) Buccal coitus

(iv) Bestiality

Codes:

(A) (i), (ii) and (iii) are correct.

(B) (ii) and (iv) are correct.

(C) (i), (ii) and (iv) are correct.

(D) (i), (iii) and (iv) are correct.

Answer: (D)www.netugc.com

50. The criminal responsibility of a mentally ill person is stated under the following section of Indian law?

(A) CrPC 84

(B) CrPC 80

(C) IPC 84

(D) IPC 80

Answer: (C)

1- Dying declaration is to be preferably recorded by (A) Doctor (B) Police (C) Magistrate (D) Jury Member Answer: (C)

Solved Objective Question(MCQs)-Forensic Science-1st Set — Advocatetanmoy Law Library

Principles of Forensic Science

Sources:A Closer Look On Forensic Science written by Archana Singh

laws.pngLaws and Principles of Forensic Science

Introduction

Forensic Science is the science which has developed its own Laws and Principles. The Laws and Principles of all the natural sciences are the bases of Forensic Science.

Every object, natural or man-made, has an individuality which is not duplicated in any other object.

1. Law of Individuality

Anything and everything involved in a crime, has an individuality. If the same is established, it connects the crime and the criminal.

This principle at first sight appears to be contrary to common beliefs and observations. The grains of sand or common salt, seeds of plants or twins look exactly alike.

2. Principle of exchange

Contact exchange traces is principle of exchange. It was first enunciated by the French scientist, Edmond Locard. Commonly known as Edmond Locard’s maxim on Interchange.

According to the principle, when a criminal or his instruments of crime come in contact with the victim or the objects surrounding him, they leave traces. Likewise, the criminal or his instruments pick up traces from the same contact.

3. Law of progressive change

“Change is inevitable” , this also applies to object. Different types of objects may take different time spans.

The criminal undergoes progressive changes. If he is not apprehended in time, he becomes unrecognizable.

The scene of occurrence undergoes rapid changes. The weather, the vegetable growth, and the living beings make extensive changes in comparatively short periods.

Samples degrade with time, Bodies decompose, tire tracks & bite marks fade, the firearm barrel loosen, metal objects rust, etc.

4. Principle of comparison

“Only the likes can be compared” is the principle of comparison.

It emphasize the necessity of providing like samples and specimens for comparisons with the questioned items.

A questioned hair can only be compared to another hair sample, same with tool marks, bite marks, tire marks, etc.

For example

A specimen obtained by writing on the same wall, at the same height and with the same instrument and then photographed. It can be matched.

Once handwriting available on a photograph allegedly written on a wall was compared with the specimen written on paper. It did not give worthwhile results.

5. Principle of analysis

The Analysis can be no better than the sample analyzed.

Improper sampling and contamination render the best analysis useless.

The principle emphasizes the necessity of correct sampling and correct packing for effective use of experts.

6. Law of probability

All identification, definite or indefinite, are made, consciously or unconsciously, on the basis of probability.

Probability is mostly misunderstood. If we say that according to probability a particular fingerprint has come from the given source, but it is not a definite opinion.

Probability is a mathematical concept. It determines the chances of occurrence of a particular event in a particular way.

If “P” represents probability, “Ns” the number of ways in which the event can successfully occur (with equal facility) and “Nf” the number of ways in which it can fail ( with equal facility) , the probability of success is given by the formula:

7. Law Of Circumstantial Facts

“facts do not lie, men can and do”

Evidences given by eye witnesses or victims may not always be accurate.

Sometimes victims may intentionally lie or sometimes because of poor senses (such as low sight, unclear hearing), exaggeration & assumptions.

According to Karl Marx “True belief only becomes knowledge when backed by some kind of investigation and evidence”.

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Laws & Principles of Forensic Science

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Forensic Science is the science which has developed its own Laws and Principles. The Laws and Principles of all the natural sciences are the bases of Forensic Science…READ MORE….

via Laws and Principles of Forensic Science — Forensic’s blog

Forensic Expert via The Forensic Science Public Desk, India

Who is an Expert?

I am an expert in doing sketches. How? I am passionate about sketching and drawing since my childhood and still, I practice it. I take a very short time to do any kind of sketch within few minutes compared to the capability of any other common human. Hence, It can be said as he has expertise in the art of sketching and he has knowledge on sketching where he can form an opinion or comment on other work whether it is authentic, truly hard work, commendable work or possibilities and what were the possible ingredients used to make a certain sketch.

So that was an example which gives us a better understanding of who is an expert.

A person who has special knowledge and skill in a particular branch of learning and thus qualified to give his opinion, whereas, an ordinary person is not competent to do so.

Thus, Doctors, artists, engineers, surveyors, engravers, mechanics, artisans, and the diverse classes of specifically skilled workmen would all be experts within the meaning of the expert, of course, each in his walk of life.

How can you be one? 

Crimes are associated with the number of evidence like blood, bullet or a dead body. Identification or classifying any of this would easy due to definite science which is available as the experience of individuals working with a field like serologists, Ballistic experts or Doctors. This particular aspect can be learnt and it can apply to

Section 45 in The Indian Evidence Act, 1872

Opinions of experts.—When the Court has to form an opinion upon a point of foreign law or science or art.

What is foreign law or science or art? Means, Court is represented by personnel’s dealing with law and justice enforced for public welfare. I pursuit of justice there are certain aspects which are also involved like science. Representatives of court, that is judges or law Practitioners are not aware of these particular sciences like serology or physics or medicine nor they can complete the degree in few days nor they can be unethical by justifying anything on their own. They are knowledgeable personnel’s in enacting law and justice for public welfare but not to justify truth hidden within the scientific evidence like nature of injury on the body or striation marks on the bullet.

Hence, the Court needs to rely on expert opinion to understand the significant scientific evidence role of any kind of case dealt with in the court.

Examples

Doctor: As to ascertain the cause of death or time since death

Chemical examiner: identification of a questioned substance by conducting chemical examination which approved by scientific statutory bodies.

Ballistics expert: identification of alleged firearm by comparing test-fired bullet and questioned bullet.

Court believes science-based literature, research held and scientific principles or laws developed during a search of the reality behind happenings of many unknown things to mankind.

Whom will you handover the evidence to?

Just imagine if you are having an Evidence which is a “Document with disputed signature, questioned age of ink in the signature and contents on the questioned document” Whom will you handover the evidence to?

One who has just completed Masters in Forensic Science – has experience practice with demo samples or simulated samples or experience while in internship or project under the supervision of an expert. The court cannot rely on you leaving behind qualified experts but you should be having the capability to convince the court in the science subject matter thus makes you an expert. Anybody one who can prove or involve in the scientific examination of the evidence on the grounds of being intellectual in scientific principles and law which are in current practice by many of the recognized scientists can be referred and can be used to prove the truth hidden with evidence. This can be regarded as the private practice of forensic consultancy.

According to IEA 45, an opinion formed by an expert is based on recognized principles regulating the scientific study. The opinion so formed by a person having the necessary special skill in the subject is, therefore, the opinion of an expert in that branch of the science. Such an opinion is the opinion of an expert in a branch of science which is admissible in evidence under Section 45 of the Indian Evidence Act. (or)

One who has 10 years of experience dealing with similar types of cases as an expert – Similar kind of cases here means, there is plenty of complications involved in dealing with crime evidence. Hence, Experience will be vast and much expertise in nature. Many of the times experts may fail to form an opinion and where by the court will justify such conflict by itself being expert by considering other circumstantial evidence and facts of the case. Under section 73 IEA.

Though Section 73 deals with Comparison of signature, writing or seal with others admitted or proved. It has also relevance with the explanation given for court expertise.

Patna High Court State (Through Cbi) vs S.J. Choudhary on 13 February, 1996

Are there any designated experts recognized by the court?

Yes, Forensic Science Laboratories personnel’s under section 293 says Reports of certain Government scientific experts. Subsection 4 applies to the Government scientific experts, namely:-

(a) any Chemical Examiner or Assistant Chemical Examiner to Government; of Forensic Science Laboratories or Govt. Chemical Examiners Laboratory.

(b) the Chief Inspector of- Explosives; current position is Joint Chief Controller of Explosives (HOD) of Petroleum & Explosives Safety Organization (PESO).

(c) the Director of the Finger Print Bureau; both state level and central level.

(d) the Director, Haffkeine Institute, Bombay; as a bacteriology research Centre called the “Plague Research Laboratory”. It now offers various basic and applied biomedical science services.

(e) Director, Deputy Director or Assistant Director] of a Central Forensic Science Laboratory or a State Forensic Science Laboratory;

(f) the Serologist to the Government. Head of Institute of Serology that is Serologist & Chemical examiner or Assistant serologists.

So these people are regarded as experts in the court officially or they can also appoint assistants working with case actually under subsection 3 of Cr.P.C 293

 

This article will help to understand forensic expertise, the role of an expert in criminal justice system by providing suitable examples accordingly Indian Evidence Act Sections 45 & 73 and also gives a glance on government scientific experts under section 293 of Criminal Procedure Code.

via Forensic Expert — Forensic Science Public Desk, India

Arson Investigation Dogs Can Detect Traces of Gasoline as small as 1 Billionth of a Teaspoon via Crime Scene to Court 

Arson Canine  East  Texas Nina Lab ATF
ATF ADC, Nina
Photo: Mark Moore; Gregg County, Texas Fire Marshal

New research out of the University of Alberta – Canada, finds that dogs can detect gasoline in quantities as small as one billionth of a teaspoon.

Daisy, an accelerant detection canine from Westchester County, New York works with her partner Detective John V. Peters.
Photo: US Fire Administration

Canines have been used in arson investigations for about 30 years, beginning when the US ATF partnered up with the Connecticut State Police in 1986 to train an accelerant detecting canine (ADC) named Mattie.

Mattie was a Labrador Retriever, working for the Connecticut State Police, and she was trained to alert to 17 different ignitable liquids. We all know that Mattie and her kind have an incredible sense of smell, but just how sensitive, is amazing.

Dogs typically have about 200 million receptor cells in their noses that help them identify scents and odors, compared to about 5 million cells in a human nose. Further increasing their sense of smell is an organ located in the roof of their mouths that allows them to basically “taste” a smell.

Mando the Chihuahua
Mando

Just like a human, a dog can smell an odor that comes directly from an item, and like us, they can smell an odor left on a surface after the source of the odor has been removed, the difference is that a dog’s sense of smell eclipses ours, and it even beats electronic equipment designed for hydrocarbon detection.

In fact, man made odor detecting devices detect hydrocarbon components in the neighborhood of parts per million, where dogs an detect amounts as small as .01 micro liters. And if that wasn’t enough to favor the dog, a dog pinpoints the area of the source odor, where a man made instrument cannot.

Lastly, a dog can actually differentiate between true accelerants and similar gases that an instrument cannot do.

K9’s are often used in arson investigation, allowing investigators to locate items and debri that presumptively contains accelerants. These areas shown as “hits” by the dog will be collected, and sent to a lab for scientific analysis.

Click the link below for more info on accelerant detecting K9’s.

 

via Arson Investigation Dogs Can Detect Traces of Gasoline Down to 1 Billionth of a Teaspoon — Crime Scene to Court 

How to Catch a Liar via Brainwave Science

According to Brainwave Science an average person hears about 200 lies every day. It is no surprise as we learn how to lie in our early development stages and by the time we become adults, we get pro at lying! The only catch here is the question, ‘how to catch a liar?’

Technological advancements in different fields of crime scene investigation have drastically changed the landscape. Today, law enforcement can use technology to detect and solve criminal activity happening at the moment. The approach is more proactive than reactive. Forensic Science has completely changed the way crimes are investigated, prosecuted, and adjudicated.

Biometrics work very well to confirm the identity of the person. They are being utilized in ID cards, bank cards, phones, and other technological devices and come in various forms such as fingerprints, irises, voice patterns, and the spatial geometry of the faces, etc. Biometric systems must be able to accommodate changes to the biometric over time which may be caused by aging, illness, or injury.  Let us not forget though that external subject identification via its Automated Biometrics Identification System aims to ensure national security and public safety. It can only, however, identify the person’s identity externally, but not the mind and schemes of the person.

Brain Fingerprinting – This technique is quite ideal for discovering if a piece of information is collected in a person’s brain through EEG. It correctly measures the electric brainwaves science which helps us tap into the person’s familiarity with the crime scene. The major challenge in using this technique is the need for extensive training and the cumbersome nature of software and hardware application needs specialized neuroscientists to administer tests that may not be learned by investigators. It is more of a service-based model where the expert is needed to constantly conduct testing.

iCognative technology is the only available neuroscience-based forensic technology that is over 99.9% accurate, applicable in almost all investigations, is based on proven P300 science, has been used in over 100 real-life cases, and is virtually unbeatable. Today many countries and intelligence agencies in the world are already reaping the benefits afforded by it. To top it all it supports human rights and eliminates torture.

iCognative technology:

  • identifies criminals from innocents, detects presence or absence or information in the brain
  • specifically screens privileged information holders, specific training like IED/EOD bomb-making
  • helps apprehend terrorism and crime supporters and sympathizers
  • helps identify foot soldiers from kingpins in organized crimes
  • successfully detects intent to harm and cause violence

distinguishes between witness and perpetrator

DNA and Fingerprints are the first go-to methods for all investigations. They are accepted as a piece of evidence in the court of law. However, the issue with them is that the crime scene must remain uncorrupted and the collection of evidence must be done properly to eliminate cross-contamination. Preservation of these evidence is also a labor-intensive task that must be conducted by professionals who have been extensively trained in this field.

Lie Detector/Polygraphs are not accepted as evidence but are extensively used by law enforcement agencies to eliminate innocents from the suspects. The accuracy rates of Lie detectors or Polygraph has been hotly debated. People are able to beat them, and the interpretation of results is done subjectively by the examiner. Most psychologists agree that there is little evidence that polygraph tests can accurately detect lies – American psychological Association (APA)

 

Did you know that an average person hears about 200 lies every day? It is no surprise as we learn how to lie in our early development stages and by the time we become adults, we get pro at lying! The only catch here is the question, ‘how to catch a liar?’ Technol

UK COVID-19 Stratagy: “The key is to Remove Restrictions from those segments of the population that are at low risk of Death from Infection” via Iowa EDU

By Nic Lewis The current approach A study by the COVID-19 Response Team from Imperial College (Ferguson et al. 2020[i]) appears to be largely responsible for driving UK government policy actions. The lockdown imposed in the UK appears, unsurprisingly, to have slowed the growth of COVID-19 infections, and may well soon lead to total active […]

via A sensible COVID-19 exit strategy for the UK — Iowa Climate Science Education

Maggot Analysis with Mass Spectrometry via Locard’s Lab

A new proof-of-concept study by researchers at the University at Albany in New York has developed a mass spectrometry-based technique for the rapid species prediction of blow fly larvae for use in forensic investigations.

Entomological evidence (evidence relating to insects) has proven invaluable to forensic investigations for decades, particularly in the estimation of time since death. Insects which feed on decomposing remains, known as necrophagous insects, will colonise a body in a reasonably predictable pattern, with different insects arriving at different stages throughout the decomposition process. Different species of flies, beetles and mites are commonly encountered. Blow flies in particular will often arrive at the scene within minutes of death to lay eggs on the body. As these eggs hatch, larvae (or maggots) emerge to feed on the decomposing remains. By studying the type and age of insects present at a scene, it may be possible to estimate the time since death, or postmortem interval.

The ability to achieve this hinges on the correct identification of insect species, which is unfortunately not always straightforward. The larvae of different species of blow fly are visually very similar, thus difficult to distinguish by eye. For this reason, maggots are often reared to maturity for species identification, with adult blow flies exhibiting more distinguishing physical differences. Inevitably the rearing of maggots to adulthood is a time-consuming process that requires the expertise of a forensic entomologist.

In recent years, researchers have tried to develop more rapid approaches to insect species identification, particularly using chemical analysis. Researchers at the University at Albany in New York have been applying direct analysis in real time mass spectrometry (DART-MS) to the analysis of insect evidence to provide a rapid species identification tool. In DART-MS, the sample is placed between the DART ion source and the inlet of the mass spectrometer, allowing chemical components in the sample to be ionised and drawn into the MS for direct analysis. DART-MS requires minimal or no sample preparation and results can be obtained almost instantly. Using this technique, Rabi Musah and her team have already demonstrated the ability to determine the species of larvae, pupae and adult flies, highlighting a promising new tool in rapid species identification in forensic entomology.

However, until now this research has focused on the analysis of individual species. In a real-world scenario, maggots present on the body may consist of multiple different species, therefore any techniques developed for rapid species identification of larvae must be able to work with mixed samples. In a recent study, the team have taken the method one step further by examining the potential to identify larvae from mixed species.

Blow flies of various species were collected from Manhattan, New York. Maggots were submerged in 70% ethanol and the solution exposed to the ion source of the DART-MS to produce chemical signatures of both individual species and combinations of species. Mixtures of two, three, four, fix and six different species were analysed. Using the chemical profiles produced, a predictive model was constructed for the subsequent identification of unknown insect samples. Using this model, maggot species could be established with an accuracy of up to 94% and a confidence interval of 80-95%. Individual insect species are readily differentiated, with different species producing distinct chemical profiles. Similarly, mixtures of two different species could also be differentiated. As might be expected, samples containing a higher number of species were more difficult to differentiate.

Although only a proof-of-concept study and further validation is required, the study demonstrates that DART-MS could offer a way of rapidly determining the species of blowfly larvae, thus allowing investigators to establish which insects are present at the scene of a death and work out postmortem interval faster.

 

Beyramysoltan, S. Ventura, M. I. Rosati, J. Y. Giffen, J. E. Musah, R. A. Identification of the Species Constituents of Maggot Populations Feeding on Decomposing Remains—Facilitation of the Determination of Post Mortem Interval and Time Since Tissue Infestation through Application of Machine Learning and Direct Analysis in Real Time-Mass Spectrometry. Analytical Chem, 2020, In Press. 

A new proof-of-concept study by researchers at the University at Albany in New York has developed a mass spectrometry-based technique for the rapid species prediction of blow fly larvae for use in forensic investigations. Entomological evidence (evidence relating to insects) has proven invaluable to forensic investigations for decades, particularly in the estimation of time since […]

via Maggot Analysis with Mass Spectrometry — Locard’s Lab

ISP forensic dashboard provides accountability & transparency —WCIA.com

ILLINOIS (WCIA) — The Illinois State Police Forensic Services Command (FSC) unveiled a new resource to provide more transparency and accountability to the public. A forensics dashboard, updated monthly, will show the number of case assignments and completion times including details for each section of the lab, the average number of days it took to […]

via ISP forensic dashboard provides accountability & transparency — WCIA.com

4 alternative ways to analyze personality via Inspiring enlightened living

“Why am I as I am? To understand that of any person, his whole life, from birth must be reviewed. All of our experiences fuse into our personality. Everything that ever happened to us is an ingredient.” ― Malcolm X, The Autobiography of Malcolm The dawning of a new year brings a fresh opportunity to […]

via 4 alternative ways to analyse personality — Inspiring enlightened living

#Forensics: Contextual bias influences jury outcomes via CSIDDS

When police lab results are weak or ambiguous, juries commonly use non science circumstances to increase its value. https://phys.org/news/2019-10-csi-current-impact-bias-crime.html

via #Forensics: Contextual bias influences and weak forensic testing results leads to jury overestimation of guilt — FORENSICS and LAW in FOCUS @ CSIDDS | News and Trends