While television shows such as “CSI” and “NCIS” may be popular, real crime scene investigations are very different from what viewers often see on screen.
McPherson Police Department Detective Mark Brink would know, having trained in crime scene investigations in the Army’s Military Police Investigation School.
On Oct. 14 and 15 Brink conducted crime scene training for new police department trainees in McPherson.
“On the first day, we covered things like protecting the scene,” Brink said, “what to do when a suspect was on the scene, crime scene photography, sketches and diagrams and how to reconstruct scenes for investigations.”
The second day’s training covered the actual processing of a crime scene, including duties, such as collecting evidence and proper note taking, triangulation and diagramming.
Brink said, while television shows, such as “CSI” and “NCIS” presented viewers with realistic investigation techniques and tools, such programs were unrealistic in how quick and simple they presented scene processing and evidence gathering to be.
“They show a lot of processes,” Brink said, “but in the real world it takes a lot longer to get results back. There are always other cases going on, and when you have to send something to a lab, they have to fit you into the schedule. There’s a lot going on. They might show an investigator getting a DNA profile through putting a drop of blood through a computer, and it’s not that simple or quick.”
Among the techniques officers learned in the training was the use of magnetic and super glue print retrieval.
“Regular fingerprint powder is an ash,” Brink said. “When you use it, the dust goes into the air and gets on other things. Magnetic fingerprint dust is applied with an electric wand that holds the particles in a ball on the end making it easier to apply without the mess.”
Super glue print retrieval involves inserting an item that may have prints on it into a plastic tank. Inside the tank a drop of super glue is heated, and the super glue molecules in the vapor stick to the surface of the object, creating a permanent print.
“With powder, the print is destroyed when we collect it,” Brink said. “With this technique, we have a permanent print to work from.”
Another print retrieval technique is the use of Ninhydrin. Ninhydrin adheres to amino acids rather than moisture.
“Where sweat and moisture can disappear over time,” Brink said, “amino acids tend to remain far longer. Ninhydrin’s been used to take prints that have been 200 years old.”
Page 2 of 3 - As a detective, the first things Brink said he takes note of are weather conditions and the positions of objects in the scene.
“Even in a house or building,” Brink said, “environmental conditions can influence things. If we’re investigating a death, environmental factors could have affected the rate of decay. Or, it could be a case where it hasn’t rained in a while, but the scene has muddy shoe prints.”
Safety and supplying medical assistance is a priority upon arrival at a scene, Brink said.
“If the suspect is on scene, it’s crucial to establish the safety of everyone there and take him or her into custody,” Brink said.
Those who might be on scene who aren’t suspects are taken to be interviewed to gather information.
Brink said scene photography involves taking photos to create a 360-degree view of the scene, as well as taking photos of the overall items of interest at the scene.
“We’ll take two photos from opposite corners,” Brink said. “Video is also a good tool to use for this.”
Officers also learned how to cast tool marks. The process involves filling the mark or puncture with a silicone material, which is later extracted to examine as evidence.
“Tools of any kind can cause certain striations,” Brink said. “We can send a cast to the lab and later match it up with the tool that was used.”
While films and television have tended to present police interviews as often intimidating or even violent, Brink said this isn’t the case.
“An interview is just a process of getting information,” Brink said. “Except for the topic, an interview is no different than a job interview. They’re not intended to be intimidating. Sometimes questions might come across as intimidating, and, depending on the situation, questions may seem pointed, but that’s never the intention.”
Brink said knowing how to properly process a crime scene and gather evidence is a very important skill for police officers.
“We get one chance to do it and do it right,” Brink said. “It’s a real challenge sometimes. There are a lot of factors that can come into play with a crime scene investigation. But if we can get the evidence and tie a suspect in, we’ve done our job.”
Brink said officers are required to take a minimum of 40 hours of continuing education training per year.
“I believe the training went very well,” Brink said, “and officers who’ve gone through it before said it would help them in the academy.”
Page 3 of 3 - Contact Jeremy Webster by email at email@example.com and follow him on Twitter @WebsterSentinel.