Forensic investigators use alternate light sources to identify evidence, such as hidden blood or biological stains that aren’t visible to the naked eye. Blood that’s been spilled and cleaned up may still be found years later by exposing the invisible stain to chemicals or light waves, which cause the area to glow or fluoresce under certain conditions. Photo Dale Stockton
The Thermo Scientific TruNarc analyzer.
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In recent years, the cold case methodology has quietly evolved to a new process that’s much more complex and elaborate. The following developments are now standard cold case practices used to pursue and link murderers to their crimes, obtain convictions and bring some sense of closure and justice to victims’ families.
Examination of Written Documents
Those struggling to get to the bottom of a cold case usually believe that the case file already contains the identity of the killer. They’ve probably been interviewed or interrogated years ago as the suspect or witness. Original written documents or statements made by these people can be reviewed with new analytical techniques. Very similar to body language, which reveals deception, human beings write out statements that give away phrases and patterns. These phrases and patterns dramatically show the writer is lying or omitting essential details. Reexamining these old documents is akin to being able to see the original state of mind of the defendant and may provide significant clues to the truth.
Evidence Identification by Use of Chemicals
Another new tool used by forensic investigators involves a series of chemicals and alternate light sources that identify evidence, such as hidden blood or biological stains that aren’t visible to the naked eye. Blood that’s been spilled and cleaned up may still be found years later by exposing the invisible stain to chemicals or light waves, which cause the area to glow or fluoresce under certain conditions.
New cold case protocols have also benefitted from information-sharing initiatives among law enforcement that started after 9/11. The cooperation between federal, state and local agencies was encouraged and mandated at the national level, and these initiatives resulted in great facilitators to general criminal investigations, as well as to cold case crimes.
LinX is a program that provides participating LE partner agencies with secure access to regional crime and incident data. It enables investigators to search across jurisdictional boundaries. Users are able to see reports, photos and historical contact information from various partner jurisdictions and use computer-based link analysis to show correlations or reoccurring hits.
CODIS is a DNA database maintained by the FBI that stores DNA profiles submitted by federal, state and local crime laboratories in the U.S. All 50 states have passed DNA legislation authorizing the collection of DNA profiles from convicted offenders for submission to CODIS. Submission of evidence from old crime scenes for identification and comparison with known samples has led to a number of resolutions in violent crimes and cold case homicides. Cold investigations have gone red hot when recent arrest-based DNA profiles hit the CODIS system. It’s much akin to leaving fingerprints at the scene with no similar prints on file with the FBI until years later.
The National Center for Missing and Exploited Children helps with searches for missing children, performs database research and battles child pornography. NCMEC sends out missing child posters and mailings, and the program is even able to do projected mock-ups of dated photos to show what a child may look like years later.
Changes in our society have also resulted in enormous amounts of personal data being recorded and viewable via the Internet. Investigators with simple Internet access can routinely find records documenting a suspect’s movements over a period of years in mere seconds. Birth, marriage, divorce, real estate, newspaper citations and personal information about friends, hobbies, travel or current location may all be viewable via deep web search engines and voluntarily posted via social media sites like Facebook.
Forensic science related to DNA has continued to advance by leaps and bounds. Today, laboratory technicians are now able to extract identifiable evidence from wider ranges of products using smaller submitted samples. With the development and practical application of DNA testing in criminal forensics, the amount of resulting data routinely provides the DNA map to match a drop of blood or saliva to a suspect with a mathematical certainty that exceeds the population of the earth.
One of the most revolutionary processes since the development of DNA testing is known as “Touch DNA.” It’s a forensic method for analyzing DNA left at the scene of a crime or brushed onto items through casual contact that only requires very small samples for testing. For example, skin cells may be left on an object after it’s been briefly touched, much like leaving a fingerprint. Touch DNA analysis only requires about seven or eight cells from the outermost layer of human skin.
Old evidence that’s been sitting sealed up on evidence shelves for many years is being evaluated and submitted for Touch DNA analysis. Those dead skin cells never left the packaged evidence and don’t “go bad” or spoil. Surfaces that have been previously dusted for fingerprints or submitted to cyanoacrylate fuming are analyzed by Touch DNA, which has also been used to analyze DNA on surfaces that were recovered from underwater crime scenes and on the brass of expended cartridges.
Blood Splatter Analysis
This isn’t a new study, but has continued to develop as a valuable investigative technique. In unsolved cases, specialists can review old evidence and determine direction of impacts, trails indicating movement and identification of low- and high-velocity impacts. This information can explain a great deal about a weapon, how it may have been used and where it was in the room, even if no weapon was found at the death scene.
New Cold Case Team Members
Police investigators, criminal analysts, forensic experts and cutting-edge scientists are now routinely staffed to cold cases. Team concept has replaced that of a single detective pouring over old files with a pencil and a pad of paper.
Criminal analysts use computers to hunt for data, trends and patterns and to crunch numbers to provide leads and insights to the detectives. They’ve been plugged into cold cases to develop targeting packages for suspects, review and identify phone records, map cell phone towers, locate financial records and provide link analysis of previously unconnected or unobserved information. They use a variety of software to sift and collate data, which may be helpful to display and organize the information in graphic presentations suitable for viewing by prosecutors or in court.
Forensic consultants in a variety of evidence-related fields may be called upon to review old crime scenes, case files, photos or physical evidence. They may be involved with creating 3D recreations of crime scenes, evaluating old evidence for use with new computer or scientific-based analysis, recreating faces on skulls or helping to gather fresh biometric hair, DNA or trace evidence. The consultant may be an expert in a single field or a jack-of-all-trades.
Forensic psychologists create profiles of killers based upon observed behaviors and crime scene evidence. They’ve also been used to do “psychological autopsies” of victims to try to recover their thinking or behaviors prior to death. They’ve been very effective working with investigators to understand a suspect’s criminal motives and behaviors, but also in suggesting ways to approach suspects—how to talk, act and even dress for showdown interviews with suspects. Forensic psychologists have reviewed recorded interviews and written statements and even performed live interrogations in an effort to bring yet another viewpoint to bear on the murderer.
With these new protocols and scientific developments in play, detectives now regularly apply behavioral and technological developments to cold cases, solve the “unsolvable” murder and bring the offender to trial.
Product Spotlight: Narcotics Identification
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