You’ve seen it countless times.
The police inspect the crime scene and find a piece of evidence: a tuft of hair, a sample of blood, a bullet casing. It goes to the lab, and after it is analyzed by forensic scientists, the evidence helps land the criminal in jail.
Or, forensic science is similarly depicted on “CSI” or “Law & Order.” But in reality, forensic science is often far more complex.
How accurate is forensic science?
What exactly is forensic science, and how does it work in actual criminal investigations? Read on to learn more about the role of forensic science in the solution true crime cases,
What is forensic science?
Forensic science, also known as criminalistics, is the use of scientific methods to assist professionals in the criminal justice system. It uses multiple scientific disciplines, such as chemistry, physics, and biology, to determine what exactly happened at a crime scene, whether it was a murder, sexual assault, or robbery.
San Francisco Police Department crime scene investigators document the scene of the January 18, 2011 shooting. (Lee Suzuki/The San Francisco Chronicle via Getty Images)
How does the forensic science process work?
It begins with thorough documentation of the crime scene. The area is photographed, bullet holes are measured to determine the trajectory of the bullets, and potential witnesses are interviewed.
Physical evidence, which may include fingerprints, blood or DNA samples, and possible murder weapons, is collected. These items are then sent to the laboratory for analysis.
Victimology, or studying victims to gain information about a perpetrator’s behavior, is also an important component of forensic science.
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Mary Ellen O’Toole, Ph.D., director of the Forensic Science Program at George Mason University and a former FBI Special Agent As with the behavior analysis unit, victimology begins by considering several questions.
“Why was that victim chosen and did the perpetrator know that victim? What was the level of risk to the victim? Was this someone who was victimized in their own home in a safe neighborhood?” he told Fox News Digital during a phone call.
Finding answers to these questions can help shed light on the offender’s behavior and possible motives. O’Toole said that at this point in the investigation, “I’m still looking at the whole case, but I’m already forming some tentative opinions.”
St. Paul Police Officer Ron Himes demonstrates the process of digitally imaging evidence in a crime lab. (Bruce Bisping/Star Tribune via Getty Images)
Criminal investigation and ‘order of operations’
When it comes to testing, it is essential to do things in the right order.
Investigators have to make important decisions about simple things like how to move through the scene: Do you enter the bathroom first, or the bedroom? It’s important to be careful when a mistake could disturb or ruin potential evidence.
This is especially important when objects are examined in a laboratory. Some tests may destroy important evidence on the object.
Peter Valentin, Ph.D., chair of the forensic science department at the University of New Haven and a former detective in the Connecticut State Police Major Crimes Squad, “Think of a firearm,” he told Fox News Digital during a phone call. , “You might want to know whether the gun works or not. But if you send it to get operability testing first, and you don’t realize until later that there was biological evidence on that gun, it’s quite possible that “That evidence will be destroyed. It will be destroyed or altered to its original form.”
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That’s why non-destructive testing should be done as early in the process as possible.
As test results come in and more information becomes available, investigators are able to build a complete picture of what happened at the crime scene. They may have a hypothesis about what happened based on their first look at the scene, but sometimes, the visuals can be deceiving.
A death that appears to be from natural causes may be murder, or vice versa. This is why forensic science can provide objective data that helps them formulate an idea of how a crime occurred.
Forensic Science: ‘Connecting objects, people and places’
According to the Bureau of Justice Statistics, forensic science helps investigators collect evidence and then establish connections “between a person suspected of committing a crime and a crime scene or victim.”
When Valentin explains this concept to his students, he focuses on three things. “Forensics is about linking people together, linking people to objects, and then linking people and objects to places,” he said.
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For example, he points to the ongoing case idaho college massacre, The prime suspect, Brian Kohbarger, was discovered when investigators found a DNA match on a stack of knives used to murder four students.
Instead of going through thousands of hours of surveillance footage, investigators were able to narrow the search to a specific vehicle and a specific cell phone serial number. Thus they determined that Kohbarger was in the vicinity of the crime scene at the time of the murders.
“This is a great example of how you can use forensic information to focus your investigation,” Valentine said. “You range from having a ton of data to having a suspect from out of state, and his car is in the area during period of crime, “Maybe that’s enough evidence to convince the jury.”
Boston Police criminalist Amy Kratz uses a microscope in the Boston Police crime lab. (Mark Garfinkel/MediaNews Group/Boston Herald via Getty Images)
Crime Scene Analysis: Patience Pays Off
One way that forensic science differs from the way it is portrayed on television is the time it takes to obtain results. Typically, the analysis takes only a few hours. In reality, it may take days or weeks.
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In the case of Gary Leon Ridgway, “Green River Killer,” One of the most prolific serial killers in American history, it took more than a decade for one piece of evidence to catch him.
Ridgway committed several murders from the 1980s to the early 2000s. Investigators considered him a suspect and even collected a saliva sample from 1987, but there was not enough evidence to convict him.
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DNA profiling was still in its infancy in the 1980s. However, technology developed rapidly over the coming decades, and in the early 2000s, a DNA test linked Ridgway’s saliva sample to DNA collected from murder victims.
“It may take years, but that’s what forensic science is,” O’Toole said.
