History & Careers

History of Forensic Science

Notable Names

  • Victor Balthazard (1852-1950), French 

  • Medical examiner that analyzed firearms & hair samples 

  • Created advanced photographic method to identify & compare marking of different bullets/firearms

  • Verified the uniqueness of fingerprints


  • Alphonse Bertillon (1853-1914), French 

  • Developed first systematic method to identify suspects/criminals

  • Method was based on anthropometry (Bertillonage) 

  • Used 11 body measurements with information & visuals 

  • Bertillonage was used all over the world into the 20th century before replaced by accurate method of fingerprinting 

  • Sir Francis Galton (1822-1911), English 

  • Credited with developing first fingerprint classification system

  • Published influential book Finger Prints in 1892

  • First to classify fingerprints based on arches, loops, & whorl 


  • Dr. Calvin Goddard (1891-1955), American 

  • Established scientific examination of firearm evidence in USA

  • Joined the Bureau of Forensic Ballistics in 1925

  • Worked in FBI to develop tools in forensic firearm analysis like comparison scope


  • Hans Gross (1847-1915), Austrian

  • Coined criminalistics for forensic analysis 

  • Published the first forensic science textbook in 1893


  • Edmond Locard (1877-1966), French 

  • Main interest was microscopic trace evidence & strongly believed in importance of linking people to places

  • Developed Locard’s exchange principle: 

  • Every person-person or person-place contact results in transfer of materials between them 


  • Matieu Orfila (1787-1853), Spanish Forensic Toxicologist 

  • Focus was on studying poisons, more specifically arsenic 

  • Developed techniques to detect arsenic in blood, tissues, etc.


  • Sherlock Holmes, Fictional Character created by Arthur Doyle 

  • Stories of Sherlock played a major role in shaping the public image of forensic science 

Science & the Law Today

The Adversarial System 

  • Law uses this system in which lawyers represent 1 of 2 rival positions arguing for a cause 

  • This system contradicts with the scientific method, as lawyers & scientists place emphasis on vastly different aspects of the same case


Forensic Science

  • Forensic science helps by:

  1. Distinguishing evidence from coincidence 

  2. Ranking possible results

  3. Using certainly & probability when needed 

  4. Avoiding unlikely assumptions 

  5. Moving from general ideas to specifics

  6. Testing hypotheses step-by-step


  • Forensic scientists work to create justified explanations, similar to clinical medicine 

  • They must hold their opinions with contrite fallibilism, recognizing the limits of their knowledge & the potential for error


Modern Practice of Forensic Science

  • Scientists can work in both public or private laboratories 

  • Public laboratories are funded by government 

  • Private laboratories are businesses that are designed to make a profit

  • Laboratories usually cover DNA, drug analysis, firearms, trace evidence & fingerprinting 


Accreditation & Certification

  • Accreditation: laboratory has agreed to operate according to a industry standard & can show proof of this standard 

  • Certification: scientist has completed a written test covering their discipline & participates in yearly proficiency tests 



Types of Legal Proceedings

US legal system divided into criminal & civil law: 

  • Civil cases are between individuals or parties

  • Criminal cases involve government entities charging the party responsible of crimes

  • Jurisdiction= a region over which law enforcement or legal entities can excise authority 


  • Evidence presented at court is called the trier of fact 

  • A grand jury decides whether the evidence is against a defendant warrants 

  • To determine the punishment of crimes, it requires the consideration of the type of criminal charge: 

  • Felonies: are serious criminal cases with more severe punishments 

  • Misdemeanors: minor offences with less severe punishments 


A Forensic Point of View: 

  • After a laboratory analysis, a report is submitted to the party who sent the evidence & shared with the prosecuting attorneys 

  • Then the scientist will be sent a subpoena, that states the details of the trial

  • Prosecution begins with direct examination to admit evidence, which the defence can challenge

Rules of Evidence

  • Evidence is court-approved info that can be used when making a decision on the defendant 

  • Ex. photos, physical evidence, DNA

  • Info must be pass the screening function to be accepted as useable evidence 

  • Rules of evidence is meant to filter out any irrelevant or inappropriate information presented by any side 


Frye Standard

  • Originates from the 1923 Frye v. United States case

  • Ruled that scientific evidence is admissible court only if it is “generally accepted” by relevant scientific community

  • Aimed to ensure that unreliable to untested methods weren’t used in legal proceedings


Daubert Standard 

  • Set guidelines for using scientific evidence in court 

  • Requires that evidence is reliable, relevant, & based on tested, peer-reviewed methods 

  • Judges act as “gatekeepers” to decide if the evidence meets these criteria


The Daubert Trilogy 

  • 2 later cases built upon Daubert's principles 

  • Joiner Case

  • Court ruled that scientific data had to pass the Daubert criteria & a relevance test


  • Kumho Tire Case

  • Extended the Daubert ruling to all relevant experts, not only scientists


Categories of Evidence

  • Inculpatory Evidence: 

  • Shows a person’s involvements in an act & establishes guilt

  • Exculpatory Evidence:

  • Excludes a person as a source, tends to clear defendant of guilt 

  • Direct Evidence: 

  • Info that directly establishes a fact for which the info is offered 

  • Ex. eyewitness testimony that the defendant committed a crime

  • Circumstantial Evidence: 

  • Allows trier of fact to accept info for which direct evidence is unavailable by inferring from direct evidence 

  • Ex. blood is found at crime scene & linked to defendant through DNA test

  • Reconstruction Evidence: 

  • Provides info about the events that occurred before,during, & after the crime


  • Associative Evidence: 

  • Often used for reconstruction a crime scene & used to associate or disassociate a suspect to a crime

  • Ex. hair, fibers, bodily fluids, glass, firearms, etc.


  • When comparing class-characteristics & identifying evidence, examiners must convey meaning or significance of results

  • *class-characteristics evidence refers to features that link an item to a group but not a specific individual

  • Ex. a shoe print matching a type of shoe(like size or brand) but not identify the exact shoe it came from

  • For class-characteristic evidence, examiners must try to distinguish questioned samples from known standards


Scientific Groupings

  • Biological evidence

  • Typically human tissues/fluids used for identification & DNA testing 

  • Chemical Evidence: 

  • Seized drugs, toxicological samples, materials chemistry, explosives 

  • Trace Evidence: 

  • Items left behind at crime scene 

  • Questioned Documents: 

  • Common examinations include handwriting comparisons, alterations, obliterations, & ink/paper characterization

  • Fingerprint Evidence: 

  • Latent print development & fingerprint identification are useful technologies in forensics 

  • Impression Evidence: 

  • Footwear & tire impressions are common

  • This evidence can provide substantial info depending on quality 

  • Firearm & Tool Mark Evidence: 

  • Type of impression evidence encompassing fired bullets, cartridge casings, & shells