Forensic microscope is latest crimefighting tool
By Bob Allen
Northeast Booster (MD)
January 3, 2007
Thanks to the Baltimore County Police Foundation, the county police department has a new and improved perspective on crime.
A perspective vthat's magnified 80 times.
Recently, the Baltimore County Police Department's forensic lab began using a state-of-the-art, $66,000 Leeds Firearms and Toolmarks comparison microscope to run ballistics tests and compare forensic materials. The microscope was purchased by the nonprofit police foundation with funds donated by its member businesses.
Magnification is only one of the unique features of the computerized, high-precision instrument.
"This is our first equipment purchase" for the department, said Parkville resident Charles Norris, a retired county police officer who has served on the foundation's board since 2000.
Norris, a former commander of the department's Parkville precinct and former head of the department's legal division, said the purchase of the microscope is in keeping with the foundation's mission: Providing private-sector financial, technical and professional support to the police department.
In clearer focus
According to County Police Chief Terrence Sheridan, the department's firearms identification unit already has two microscopes for running forensic comparisons of bullets and tool marks left at crime scenes.
But Sheridan, who spoke during a public demonstration of the new microscope last month at the department's crime lab, said the new Leeds instrument is both more powerful and more versatile than the older microscopes.
"This is a gigantic step for us in terms of technology," Sheridan said of the custom-designed instrument. "It enables our technicians to do a much more efficient job."
One advantage is the new microscope's larger field of view. It lets technicians examine a larger portion of a highly magnified piece of evidence such as a bullet slug, a cartridge casing or the distinct impressions often left by a crowbar or other pry tool. This increases both speed and accuracy in the comparison process, Sheridan said.
Cpl. Mark Ensor, a ballistics specialist with the police department, said examining and comparing the microscopic impressions left on bullet cartridges and shell fragments is a tedious process that can take up to a week.
"This (microscope) can save a day or two in that process and also produce more conclusive results," Ensor said.
"It far exceeds the capacity of the microscopes we already have," he said. "It is quicker, has more clarity and causes less eye strain."
Ensor explained that when a firearm is discharged, the grooves and patterns of the barrel's rifling impression leave a distinct "fingerprint" on the bullet as it spirals through the barrel. A similar, one-of-a kind impression is left on a shell casing's breech face when the gun's firing pin strikes it. A gun's extracting mechanism also leaves distinct markings when it ejects a spent cartridge from the firing chamber.
Ensor said the new Leeds microscope has 12 different magnification settings -- twice as many as the lab's older microscopes -- ranging from six times to 80 times actual size.