Crime scene investigation is an art. It requires meticulous attention to detail and the ability to observe and solve problems on site. The primary focus of the crime scene investigator is to maintain the integrity of the crime scene. According to forensic scientist George Schiro, crime scenes are often compromised by first responders or others who are untrained in evidence collection and chain of evidence protocol. Taught in a classroom setting, the required skills become part of a curriculum in which students learn by participating in shadowing programs, mock classroom demonstrations or computer interactive resources.
The techniques used by the interviewer to obtain information from a witness determine the success of the interview. The witness should feel comfortable, so the interviewer should not appear too aggressive or intimidating. Students may practice interviewing one another during a mock criminal investigation. The instructor provides a list of appropriate interview techniques and asks students to demonstrate a method. Students should prepare open-ended, sequential questions in advance. Try to elicit assistance from the local police department who may allow students to shadow an officer interviewing a witness.
The documentation and collection of blood evidence is crucial at a crime scene. Before you actually collect blood evidence, you should take notes or pictures or videotape the evidence to preserve the integrity of the crime scene so that any later changes in the setting are immediately evident. Students can study a mock crime scene and use different methods to collect the blood, such as cutting out sections containing the bloodstain, lifting the stain off with fingerprint tape or scraping dried blood into an envelope and properly identifying and packaging it.
Biological evidence collected, such as a strand of hair, saliva or mucus in a tissue, can implicate or eliminate a suspect. Issue students cameras, gloves, tweezers, scissors, foot covers and other items. Place obscure forensic-type evidence, such as fingernails, urine and sweat-soaked clothing, throughout a simulated crime scene and instruct students to take notes, photograph and record what they find. Provide students with a list of precautions to avoid contaminating the crime scene and explain proper storage of evidence. Evaluate their performance.
Students take one another’s fingerprints and the instructor makes copies. After teaching the types of print characteristics -- loop, whorl and arch patterns -- hand out photos of a fingerprint which students must match with another print. Have them compare the print to the set of classmate prints, looking for differences and similarities. Eliminate those that are definitely not a match and continue narrowing down the possibilities until you are certain you have a match. Afterwards, students may create a PowerPoint presentation to demonstrate the methodology used to achieve their results.
- Discovery Channel; Crime & Forensics; 2010
- Crime Scene Investigator Network; Collection and Preservation of Blood Evidence from Crime Scenes; George Schiro; 2011
- National Criminal Justice Reference Service: Eyewitness Evidence: A Trainer’s Manual for Law Enforcement
- Science Super School; Fingerprint Game and Fingerprint Identification … A CSI Case Study; Donald Reinhardt; 2010
- Crime Scene Forensics: DNA
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