WASHINGTON (WUSA9) -- Any time the United States mail is used to commit a crime, you can bet the investigators at the National Forensic Lab of the US Postal Inspection Service are analyzing critical evidence.
Latent Print Analyst Stephanie Toth offered a demonstration.
"This is an Ab Roller box that we got in. They foamed the Ab Roller onto the box and then, the gun was laying in here, with plastic wrap stuffed around it," said Toth.
Piece by piece, forensic scientists carefully analyze evidence--each strip of packing tape, every section of packaging. They're searching for fingerprints.
"I'm not out there arresting people, but I'm looking at the evidence from crimes and trying to help those cops out there, those investigators do their part of the case," she said.
The work is painstaking. If analysts suspect a piece of evidence bears latent prints—those not visible to the naked eye—they'll place them in this chamber where a super glue vapor will help reveal potential fingerprints.
Added Latent Print Analyst Patty Cornell, "I get to either enter them into the automated fingerprint identification system or I get to compare them to known fingerprints that are submitted for suspects in the case itself."
This is the only lab of its kind in the country investigating crimes using the US mail. Roughly 40% of the work done here is related to the shipment of illegal drugs.
Devious criminals even try to conceal the scent of drugs they've mailed, with things like toothpaste.
"It's shocking," Toth told us. " A lot of times we'll get drugs wrapped in dryer sheets or with candles wrapped around it, so that way the dogs don't hit on it when they're doing their search of packages at the post office."
Another eye-opener: the quantity of illegal items sent through the mail. Weapons, threatening letters, counterfeit stamps.
"Some of them are really good," said Forensic document examiner Haley Elliott, showing us two sets of stamps that look identical to the naked eye.
Elliott has the experience and technology to help uncover fraud. Infrared light can even reveal differences in ink.
"It's always fascinating," she said. "Each case is a mystery. Every case is new. Whether you're looking at handwriting or you're looking at a document that they think may have been altered, you are trying to find that answer."
Federal law prohibits the US Postal Service from simply opening mail without probable cause, but often, tips from law enforcement or the general public will help lead them to illegal items.
Written by Andrea McCarren, WUSA9