Detective Doug Henry and Communications Officer Jerry Corn, with the Barry County Sheriff's Office, presented crime scene investigation information at Southwest Middle School on June 29.
"Crime scene investigation is not like CSI on television," said Henry. "It takes more than an hour to solve a crime. I have spent three days from 7 a.m. to 10 p.m. investigating a homicide."
Southwest Middle School mathematics teacher Jon Sack invited Henry and Corn to his summer school class to demonstrate the problem-solving skills required in their jobs.
"Math is solving problems. Life is solving problems," said Sack. "I want my students to learn how to solve problems by using their powers of observation, logic and reasoning."
Sack uses practical life experiences to promote the importance of mathematics in many of his daily lessons.
Henry and Corn discussed the problem-solving process used in investigating crimes around Barry County. They also demonstrated the process of lifting fingerprints from metal and paper.
When detectives first arrive at a crime scene, they rope off the area where the crime was committed, said Henry.
"You usually make the crime scene larger and then narrow it down," said Henry. "You can always make the crime scene smaller but not bigger because of contamination."
Investigators use sticky measuring tape and numbered markers to mark areas and evidence at a crime scene. As areas and evidence are marked, 35-millimeter photos are taken to document the investigation.
"I have used three rolls of film on one room during an investigation and sometimes that is not even enough," said Henry.
As detectives move around a crime scene, they must remain aware of everything in the room.
"You have to stop at the doors and look at the scene," said Henry. "You look where your feet are going before you walk, and you search the area in a pattern."
Detectives search for DNA, fingerprints, weapons, hair, fibers, blood, shoe prints, tire tracks and other physical evidence at crime scenes.
"When we are doing an investigation, first we collect everything visible then we use Luminal for further collection," said Henry.
Luminal is used to find blood and other evidence that has been covered or cleaned up.
Collected evidence is placed in secure vials, envelopes and shipping packages and sent to the Missouri Southern State University crime lab in Joplin for analysis.
Henry and Corn also discussed the importance of witness testimony and other crime-solving tools.
"Crime scene investigation takes a lot of time and patience," said Henry, "but it is fun to be able to put the bad guys away."
Sack plans to invite a traveling crime lab to set up a mock crime scene for his students at Southwest Middle School in the fall.