FRESNO, Calif. (KFSN) --Whenever there's a suspicious device involving the US mail, specialized safety teams help disassemble the package. Then it's sent off to be analyzed.
One suspicious device contained nails which was found near a collection box in Arizona.
"When you have an explosive device, you don't want to move it at all. You want to make sure that it is kept safe, then rendered safe, which means basically disassembled," said Vincent Desiderio, Forensic Chemist.
Once it is rendered safe the evidence goes to the Postal Inspection Service's Forensics Lab in Washington, D.C. Their mission: to find evidence that will assist investigators to track down a suspect or build a case.
"Handles what's known as trace evidence, that may be any small or minute particle that transfers between an item from one object to another," said Desiderio.
Desiderio is a forensic chemist who works in the physical evidence lab. Since the suspicious package was disassembled for safety the lab then reconstructs it to examine what is left behind. For example: they couldn't find any full fingerprints but they did find a partial inside a box flap.
"They were able to develop a partial DNA profile of the suspect inside the box. DNA is very sensitive right now, so you don't need that much in order to get a partial profile," said Desiderio.
Piece by piece, the work done in the lab assists in shrinking a list of suspects on that profile.
"I found some green paint inside the box that was associated with some of the components that-- the house of the suspect had green decking all around the house," said Desiderio.
Then once investigators were able to search the home they found evidence linked to the return address.
Desiderio said, "It had been photocopied and then handwritten over."
This discovery of the evidence made the case.
"In the suspect's residence, he had some photocopies and actually an original mailing that had handwriting with the same return address," said Desiderio.
The suspect, in this case, was convicted of mailing a dangerous device and got a seven-year prison sentence.