Engineering the Answer
By Robin Hegg
It’s a dark and stormy night. Red and blue revolving lights reflect off the wet brick and highlight the steam rising out of a sewer grate. As the camera pans down we see a sea of police cars and an area cordoned off with yellow police tape. Crime scene investigators snap pictures of every surface, collect samples of blood, paint, and other trace evidence, dust for fingerprints, and bag objects that might be relevant to the investigation. All of this evidence will be analyzed to help detectives piece together a picture of what happened here.
We see these investigations unfold on television dramas all the time. These shows highlight the exciting world of crime scene investigation and many of the roles involved in solving crimes. TV has highlighted detectives, CSI lab techs, medical examiners, forensic anthropologists, even entomologists. But what about engineers?
Engineers play a vital role in the investigation of crimes, both in creating technology that can help investigators get more accurate information from evidence and in using their engineering knowledge and reverse engineering skills to solve mysteries.
Advances in technology are helping to improve the types of evidence that can be found and the accuracy with which that evidence can be analyzed. Computer programs are used in the analysis of fingerprints, shoe prints, and handwriting. Each of these kinds of evidence has a large risk of human error—a partial fingerprint, mixed with an investigator’s hunch, can lead to the wrong suspect. Computer software can make sure the initial analysis is done correctly, but it can also allow investigators to see how likely it is that two suspects would have a similar enough partial fingerprint to cause such a mistake. This information can help to ensure that the wrong suspect isn’t successfully prosecuted on an unreliable piece of evidence.
Advances in computer technology have also helped in the processing and identification of DNA and in the extraction of data from computers and cell phones. Engineers have even developed virtual reality crime scene software that can allow investigators to revisit the crime scene in three dimensions. This can give them a more accurate picture of what happened than just looking at the limited photographs taken at the scene.
Brain mapping tests can let investigators know if a suspect is familiar with the crime. The test involves attaching sensors that monitor electrical activity in the brain to a suspect’s head. The suspect is then shown images or played sounds, and the tester is able to observe what parts of the suspect’s brain become active with each stimulus. Pairing our knowledge of how a person’s brain responds to seeing familiar objects allows testers to conclude whether or not the suspect recognizes the images and sounds related to the case.
Voice recognition software can help solve crimes as well. Evidence sometimes presents itself in the form of a voicemail or recorded conversation. Investigators can use voice recognition software to compare the voice of a suspect to the voice in the evidence. The software allows them to analyze the sound patterns of the suspect’s voice and of the voice on the evidence and see if the two match.
Knowledge and developments in chemical and materials engineering also aid investigators as they work to identify solids or liquids found at a crime scene, such as bullet lead and paint chips left from cars. They also help investigators to analyze trace evidence, like DNA or explosives residue, and to do toxicology screenings.
There’s even an entire discipline within engineering devoted to investigations—forensic engineering. Forensic engineers are hired as expertise to determine the cause of structural failures, fires, traffic accidents, and engineering-related injuries. They can help to establish whether someone is at fault, and if the incidents were caused by malfunctions or human error or recklessness. They can use science and math to answer questions that come up in all sorts of criminal and civil investigations.
To do their jobs, forensic engineers analyze cases, looking at evidence, taking measurements, performing experiments, and making models to help them piece together what happened at the scene of the incident. They are often hired by attorneys to act as experts in their cases. They study the case, prepare expert reports, and sometimes testify in court as expert witnesses.
Forensic engineers study in a wide range of engineering fields, including civil, mechanical, electrical, materials, and traffic engineering. This broad scope of knowledge allows them to help out in many different kinds of situations, and to look at cases from a number of angles.
With any investigation, there’s always the risk evidence that isn’t conclusive is presented as fact, or that personal or political bias will influence how the data that’s found is interpreted. That’s why the role of engineers is so important to investigations. Through technology that can limit human error and bias, the use of data comparisons, and the application of scientific rigor to the analysis of evidence, crime scene investigators and detectives can come closer to the finding the truth, fewer people will be falsely accused, and more crimes will be solved successfully.
Whether behind the scenes, creating the technology that helps crime scene investigators analyze evidence faster and more accurately, or at the scene, analyzing the evidence themselves, engineers have an important role to play in the criminal justice system and the investigation of accidents, disagreements, and crimes.