The end of 2012 turned into the start of a busy investigation period for the Grand Rapids Forensic Science Division.
Grand Rapids' six deadly shootings in December brought the crime lab's case-load to an estimated 1,960 cases for the year, according to laboratory director, Lieutenant James Pierson.
"About 1,150 actually came from metro Grand Rapids," Lt. Pierson.
Lt. Pierson says shootings put everything else on the back burner.
"Any evidence submitted by the agencies has been given a high priority," he said.
Because cameras are not allowed in the Grand Rapids lab, we went to the Michigan State Police Forensic Science Division in Lansing to see just how the process works.
"These are the firearms, these are fired shotshells," said Sgt. Jeff Amley, firearms examiner with MSP.
Both are from a fatal shooting.
"I would test-fire the firearms for functionality to make sure they functioned during the shooting incident," he said.
This is Sgt. Amley's speciality, reconstructing a crime scene.
His test-fires help identify or eliminate a certain gun, as well as bullets.
In the shooting room, he picks out the same type of ammunition used in a crime, and shoots it into the water recovery tank.
The water slows down the bullet's velocity.
"It preserves the bullets in as much of a pristine way as we can," he said.
That process helps to identify the weapon in unsolved shootings.
In the indoor fire range, Amley tests larger firearms to determine the range of a gun fired in a crime.
He also trains his examiners to shoot at multiple objects that a shooter would at a crime scene, including windshields and windows. Certain materials expand and contract in different ways when hit by a bullet, so bullet sizes can look misleading.
It's in the lab where Sgt. Amley spends most of his time, under the microscope, comparing bullets.
The key tool firearms examiners use is the comparison microscope. It allows them to look at two different pieces of evidence at the same time, such as a fired cartridge case.
"We look to see if it was damaged, if it was tarnished, if the cartridge case was ruptured," said Sgt. Amley. "In this case I have 67 pieces of evidence."
One tiny mark can make all the difference.
"This is elliptical shape, while this is more circular."
Based on this, Sgt. Amley determined they weren't fired out of the same gun.
It's one step closer to helping authorities find their suspect, or maybe, suspects.
It's tests like these that can help police close cases and give some answers to the families of shooting victims.
When guns aren't found at crime scenes, investigators put bullet cartridge samples into a national identification database to compare them with other shootings.
So far, MSP has made more than 100 successful matches.