forensics chs mcniff

ForensicsCHSMcNiff

Vocabulary• CRIME SCENE: Any physical location in

which a crime has occurred or is suspected of having occurred. – PRIMARY CRIME SCENE: The original

location of a crime or accident. – SECONDARY CRIME SCENE: An alternate

location where additional evidence may be found.

Vocabulary

• SUSPECT: Person thought to be capable of committing a crime.

• ACCOMPLICE: Person associated with someone suspected of committing a crime.

• ALIBI: Statement of where a suspect was at the time of a crime.

Processing Versus Analysis

Crime scene investigations have two aspects: processing & analysisProcessing follows a series of standards steps

Processing Versus Analysis

Analysis depends on: detailed observation, proper processing, making logical connections, laboratory analysis, analysis of scene patterns, and integrating all the data availableCrime scene analysis follows the steps of the Scientific method

Types of ScenesTwo major categories of criminal activities having crime scenes:

property crimes (larceny, burglary, auto theft)crimes against persons (assault, battery, sexual assault, robbery, murder)

Types of Scenes

The nature of the scene will affect the way it is handled:

indoor or outdoorpublic or private property

Initial Actions & Scene Security

Initial actions of the first responders include:

Rendering aid and assistance to the victimArresting any suspectsDetaining any witnessesNoting initial scene conditionsSecuring the scene

Initial Actions & Scene Security

Crime scene security is needed to preserve the integrity of the sceneOnce the exigent emergency situation is resolved, subsequent actions at the scene will require a warrantDuties and Responsibilities of the First Responders at the Crime Scene

Secure & Isolate the Crime Scene

First priority is medical assistance to individuals & arresting the perpetrator.Ropes or barricades and guards will prevent unauthorized access to the area. Every person who enters the crime scene has the potential to destroy physical evidence.

Secure & Isolate the Crime Scene

The lead investigator evaluates the scene & determines the boundaries. They do an initial walk through & develop a strategy.All items must be documented & photographed.

Steps in Scene Processing & Analysis

Scene Survey & Evidence RecognitionScene SearchesDocumentationEvidence Collection & PreservationRelease of the Scene

Scene Survey & Evidence Recognition

A scene survey is an initial walk-through to establish the type of scene, note any transient evidence, and recognize any potential physical evidenceTransient evidence is evidence that is easily destroyed or compromised

Scene Survey & Evidence Recognition

Evidence recognition is the determination of which physical evidence is relevant to the case as opposed to being part of the background

Types of Evidence

Transient EvidenceOdor, Temperature, Imprints and indentations, Markings, Vapor

Pattern EvidenceDirect Contact: Person/Object, Object/Object

Types of Evidence

Conditional EvidenceLight, Smoke, Fire, Location, Vehicle Status, Body Status

Transfer EvidenceClassification, Physical Evidence

Fundamentals for the Scene

SecureAid for victim, apprehension of suspect, integrity

SearchRecognition/Identification: Critical, Supporting, Superficial

Systematic Search

Fundamentals for the Scene

RecordSeveral Ways

ReconstructionHow does it all fit together

Photography• The crime scene should be unaltered,

unless injured people are involved, objects must not be moved until they have been photographed from all necessary angles.– If things are removed, added, or positions

changed the photographs may not be admissible evidence.

Photography• Photograph completely

–Area where crime took place & adjacent areas

Photography• Various angles if crime scene includes a

body:– Take photos to show body’s location &

position relative to the whole crime scene– Take close-up photos of injuries & weapons

lying near the body– After the body is removed, photograph the

surface underneath.

Photography• When size is significant, use a ruler or

other measuring scale• Digital cameras allow for enhancement &

examination in fine detail.• Videotaping a scene is also becoming

popular.

Sketches• Once photos

are taken, sketch the scene.

Sketches• A rough sketch is a sketch, drawn at the

crime scene, that contains an accurate depiction of the dimensions of the scene & shows the location of all objects having a bearing on the case.–All measurements are made with a tape

measure–Show all items of physical evidence–Assign each item a number or letter

and list it in the legend–Show a compass heading designating

north

Rough-sketch diagram of a crime scene. Courtesy Sirchie Finger Print Laboratories, Inc., Youngsville, N.C., www.sirchie.com.

Sketches

A finished sketch is a precise rendering of the crime scene, usually drawn to scale.

Computer-aided drafting (CAD) has become the standard.

Finished-sketch diagram of a crime scene. Courtesy Sirchie Finger Print Laboratories, Inc., Youngsville, N.C., www.sirchie.com.

Notes• Note taking must be a constant activity

throughout the processing of the crime scene.

• The notes may be the only source of information to refresh memory.

• Tape-recording notes at a scene can be advantageous – detailed notes can be taped much faster than they can be written.

Dealing with Physical Evidence• A forensic scientist is not usually needed

at the scene unless the evidence is complex or it is a major crime.

• Some police agencies have trained field evidence technicians.

Searching the Crime Scene• One person should supervise &

coordinate.• Include all probable entry & exit points

in search

Searching the Crime Scene• What to search for will be determined by

the particular circumstances of the crime.– Examples

•Homicide•Hit-and-run

• In most crimes, a search for latent fingerprints is required.

Ypsilanti Township, MI are looking for a burgundy vehicle in connection with a hit-and-run accident that critically injured an 11 year-old boy

Collect Physical Evidence• Physical evidence can be anything from

massive objects to microscopic traces.• It may be necessary to take custody of

all clothing worn by the participants in a crime.– Handle carefully & wrap separately to avoid

loss of trace evidence.

Collect Physical Evidence• Critical areas of the crime scene should

be vacuumed & the sweepings submitted to the lab for analysis.

• Mobile crime-scene vehicles carry supplies to protect the crime scene; photo, collect, & package evidence; & develop latent fingerprints.

Collect Physical Evidence• The integrity of evidence is best

maintained when the item is kept in its original condition as found at the crime scene.

• The entire object should be sent to the lab.

• If evidence is found adhering to a large structure, remove specimen with forceps or other appropriate tool.

Collect Physical Evidence– In the case of a bloodstain, one may either

scrape the stain off the surface, transfer the stain to a moistened swab, or cut out the area of the object containing the stain.

Collect Physical Evidence• Each different item or similar items

collected at different locations must be placed in separate containers.

• Packaging evidence separately prevents damage through contact and prevents cross-contamination.

Mock Crime Scene: http://www.masss.gov

What evidence would you collect?

Refrenceshttp://www3.sc.maricopa.edu/ajs/crime_scene_technician.htm

Bilous, Peter. Introduction to Forensic Science and Criminalistics. Washington: Eastern Washington Univesity, 5 May 2002. PPT

Pics– http://www.florida-criminal-lawyer-blog.com/2009/09/property_crime_up_in_broward_c.html– http://www.citylinks.org.uk/Images/content/84/163229.jpg

• Bug pic– http://1.bp.blogspot.com/_6QSuOepyXPE/SlJutRXLJII/AAAAAAAADPg/PEpeaUgkuyo/s400/lubber.JPG– http://thedebodeq.webs.com/apps/blog/show/prev?from_id=5880111– http://www.csialliance.org/the-basic-steps-to-become-crime-scene-investigator-career/– http://www.google.com/imgres?imgurl=http://wc1.smartdraw.com/examples/content/Examples/10_Legal/

Crime_Scene_Investigation/Crime_Scene_-_Public_Restroom_– http://www.newsday.com/long-island/suffolk/victim-s-family-asks-public-for-help-catching-killer-1.2100728– http://emt-salary.org/emt-jobs-what-you-must-know/– http://thisblogsuckssorry.blogspot.com/2011/03/things-id-rather-do-than-watch-prince.html– http://mmocker.com/2009/08/web-loot-hit-and-run-fail/– Ypsilanti Township, MI are looking for a burgundy vehicle in connection with a hit-and-run accident that critically

injured an 11 year-old boy