Forensic Science: Key Concepts, History, and Crime Scene Procedures

What is forensic science?

The application of science to criminal and civil laws.

What does forensic science encompass?

A myriad of professions that aid law enforcement in investigations.

Why do we look to science in our legal system?

Due to increasing crime rates, new crimes and weapons, and public and law enforcement concerns.

What does the term 'forensic' originate from?

The Latin word 'forensis,' meaning forum.

Who popularized scientific crime-detection methods?

Sir Arthur Conan Doyle through his character Sherlock Holmes.

What is Mathieu Orfila known for?

Being the 'Father of Toxicology' and publishing on the detection of poisons.

What did Alphonse Bertillon develop?

The first scientific system of personal identification and the science of Anthropometry.

Who is known as the 'Father of Fingerprinting'?

Francis Galton, who conducted the first definitive study of fingerprints.

What did Leone Lattes contribute to forensic science?

He developed a procedure for determining blood types from dried blood stains.

What is Calvin Goddard known for?

Being the 'Father of Ballistics' and developing techniques to examine bullets.

What did Albert Osborn contribute to forensic science?

He is known as the 'Father of Document Examination' and developed principles for document analysis.

What is Walter McCrone known for?

Being the 'Father of Microscopic Forensics' and educating forensic scientists on microscopy techniques.

What is Edmond Locard famous for?

Founding the Institute of Criminalistics and formulating 'Locard's Exchange Principle.'

Who was J. Edgar Hoover?

The 'Father of the FBI' who organized a national laboratory for forensic services.

What caused the growth of crime labs in the 1960s?

Supreme Court decisions emphasizing scientifically evaluated evidence and rising crime rates.

What are the levels of crime lab organization?

National, state, county, and municipal levels.

Which agency maintains the largest crime laboratory in the world?

The Federal Bureau of Investigation (FBI) in Quantico, Virginia.

What is the purpose of the Drug Enforcement Administration (DEA)?

To analyze drugs seized in violation of federal laws.

What services do crime labs provide?

Services vary based on local laws, capabilities, and budgetary limitations.

What are some basic services provided by full laboratories?

Physical Science Unit, Biology Unit, Firearms Unit, Document Examination Unit, Photographic Unit.

What is the Frye Standard?

Guidelines for admissibility of scientific evidence, requiring it to be 'generally accepted' by the scientific community.

What did the Daubert vs. Merrell Dow Pharmaceutical case establish?

That the Frye standard is not an absolute prerequisite for admissibility of scientific evidence.

What are the Daubert criteria for evaluating scientific evidence?

Testing, peer review, potential error rate, maintenance of standards, and acceptance in the scientific community.

What is the purpose of securing the crime scene?

To establish boundaries with tape, ropes, or cones and protect the area where the crime occurred and surrounding evidence.

What should be included in the crime scene log?

A detailed record of personnel movements in and out of the crime scene.

What is a key characteristic of a crime scene search?

It must be thorough and systematic, using an appropriate search pattern.

What types of physical evidence can be found at a crime scene?

Anything from large objects to microscopic traces.

When does note-taking begin for a crime scene investigator?

When the investigator is contacted and requested to report to the crime scene.

What preliminary information should be included in crime scene notes?

The identity of the person who contacted the investigator, time of contact and arrival, preliminary case information, and personnel present.

What are the advantages of digital crime scene photography?

Immediate image observation, higher resolution, and the ability to create a 3-D view of the crime scene.

What should crime scene photographs capture?

The area where the crime occurred and all adjacent areas where important acts took place.

What types of photographs are required at a crime scene?

Overview, medium-range, and close-up photographs, including close-ups with measurement scales.

What is the purpose of a narrated crime scene video?

To combine photography and notes, ensuring only one person narrates for consistency.

What is the current standard method for creating finished crime scene sketches?

Utilizing Computer-Aided Drafting (CAD) programs.

What is the purpose of the walkthrough in crime scene investigation?

To locate the perpetrator's point of entry and exit, document obvious evidence, and observe scene conditions.

What are the different search patterns used in crime scene investigations?

Line/Strip, Grid, Spiral, Wheel/Ray, and Quadrant/Zone search patterns.

Where can vehicle searches be conducted?

At the crime scene or at the police department or crime laboratory garage.

What is the importance of packaging evidence?

To ensure evidence is preserved and protected, using separate containers for different types.

What type of container is ideal for small or trace evidence?

Unbreakable plastic pill bottles with pressure lids.

What is a 'druggist fold' used for?

A method for packaging small evidence items securely.

How should biological or bloodstained materials be packaged?

They should be allowed to air-dry before being placed in wrapping paper, manila envelopes, or paper bags.

What type of container is recommended for drug evidence?

Sealable plastic evidence bags.

What special packaging is required for evidence from arson scenes?

Airtight metal or glass containers.

What should be done to biological or bloodstained materials before packaging?

They should be allowed to air-dry.

What is the Chain of Custody?

A list of all persons who came into possession of an item of evidence.

What is a Standard/Reference Sample in forensic examination?

A known sample used for comparison with evidence such as soil, blood, or hair.

How is evidence usually submitted to a laboratory?

By personal delivery or by mail shipment, accompanied by an evidence submission form.

What must be ensured when submitting evidence to prevent damage?

Prevent breakage or other accidental destruction.

What does the Fourth Amendment protect against?

Unreasonable searches and seizures without a court-approved warrant.

What are the four exceptions to the requirement for a warrant in search and seizure?

Emergency circumstances, preventing loss of evidence, searches incident to lawful arrest, and consent searches.

What was the outcome of Michigan v. Tyler regarding evidence seizure?

Evidence from the initial search was legally seized, but later searches were deemed illegal.

What are some types of physical evidence?

Blood, hair, documents, drugs, firearms, soil, glass, and fibers.

What is the purpose of examining physical evidence?

For identification or comparison purposes.

What are individual characteristics in forensic evidence?

Unique features that can be attributed to a specific source.

What are class characteristics in forensic evidence?

Features that can be shared among a group of items but not uniquely attributed to one item.

What is the Integrated Automated Fingerprint Identification System (IAFIS)?

A national fingerprint and criminal history system maintained by the FBI.

What system replaced IAFIS in 2014?

The Next-Generation Identification (NGI) System.

What is the Combined DNA Index System (CODIS)?

A system that allows electronic exchange and comparison of DNA profiles across laboratories.

What are the three indexes within CODIS?

Forensic, Offender, and Arrestee.

What does the National Integrated Ballistics Information Network (NIBIN) do?

Allows firearm analysts to digitize and compare markings on bullets and cartridge casings.

What is the purpose of the International Forensic Automotive Paint Data Query (PDQ)?

To provide chemical and color information about original automotive paints.

What is SICAR in forensic databases?

A shoeprint image capture and retrieval database.

What is the primary goal of crime scene reconstruction?

To answer the questions: Who, What, When, Where, Why, and How.

What information can bloodstain patterns reveal?

Direction of blood origin, angle of impact, position of victim/assailant, movement of individuals, minimum number of blows, and location of the individual delivering blows.

What are impact spatter patterns?

Patterns that occur when an object impacts a source of blood.

What is gunshot spatter?

Blood spatter resulting from a gunshot wound, often characterized by a drawback effect.

What is cast-off spatter?

Blood that is flung from a moving object, typically a weapon, during an attack.

What is arterial spray spatter?

Blood patterns created when blood is expelled from an artery due to a wound.

What are expirated blood patterns?

Patterns formed when blood is expelled from the nose or mouth, often due to breathing or coughing.

What are void patterns?

Patterns that indicate the absence of blood in a specific area, suggesting an object or person was present.

What are drop trail patterns?

Patterns formed by blood drops falling from a moving source, creating a trail.

What is skeletonization in bloodstain analysis?

The process where the outer edges of a bloodstain dry while the center remains wet, indicating time since the blood was deposited.

What is the area of convergence in bloodstain analysis?

The 2D plane from which drops in an impact pattern originated.

What is the area of origin in bloodstain analysis?

The three-dimensional space from which the blood was projected.

What methods are used for documenting bloodstain evidence?

Grid method and perimeter ruler method.

Why is it important for all personnel to be familiar with bloodstain patterns?

To properly record and document them for use in reconstruction.

What is the significance of surface texture in bloodstain analysis?

Surface texture can affect the appearance and behavior of bloodstains.

What is the role of specialists in bloodstain pattern analysis?

They decipher patterns either at the scene or from photographs at the lab.

What can a series of swipe patterns indicate?

They can indicate the movement of a person or object across a surface.

What is the purpose of bloodstain pattern analysis in crime scene investigation?

To reconstruct events and understand the dynamics of a crime.

What is the minimum number of blows analysis in bloodstain patterns?

Determining the least number of strikes that could have produced the observed bloodstains.

How does bloodstain pattern analysis assist in determining the position of individuals?

By analyzing the location and angle of bloodstains, investigators can infer positions of the victim and assailant.

Who disappeared in 1982?

Robert Durst

What significant event occurred on December 24th, 2000?

Susan Berman was murdered.

What was misspelled in the letter sent to the police on December 23rd, 2000?

'Beverly' was misspelled as 'Beverley'.

What is a questioned document?

A document whose authenticity is in doubt.

What are individual characteristics in handwriting?

No two individuals write exactly alike.

What are some variations expected in handwriting?

Margins, spacing, crowding, insertions, alignment, angularity, slope, speed, pressure, letter and word spacing, relative dimensions of letters, connections, pen movement, and writing skill.

How can handwriting be individualized?

Through personal characteristics like spelling, punctuation, phraseology, and grammar.

What factors can influence handwriting characteristics?

Drugs or alcohol.

What is the purpose of comparing typescript?

To examine characteristics from photocopiers, faxes, and printing devices.

What methods can reveal alterations in documents?

Infrared light can reveal alterations, erasures, and obliterations.

What is the purpose of electrostatic detection apparatus (ESDA)?

To visualize indentations in a document suspected of containing indented writings.

What can digital imaging processing do?

Make adjustments to images, such as lightening, darkening, and color contrast.

What is trace evidence?

Any physical evidence found in small amounts at a crime scene.

What are common examples of trace evidence?

Hair, fiber, paint chips, body fluids, stains, powders, explosive residue, glass particles, vegetative matter, metal particles, and soil.

What questions are important for analyzing trace evidence?

What is it? Is it man-made or natural? What is its source? How common is it? Can it be identified to a single source?

What are the two types of properties used to analyze evidence?

Physical properties (odor, color, boiling point, density) and chemical properties (elemental composition).

What can human hair evidence indicate?

It can provide a link between the criminal and the act.

What are the three principal parts of hair?

Cuticle, medulla, and cortex.