A Warren man has learned his fate after drug agents used GPS tracking and invisible dye to trace a package that once contained a brick of Fentanyl.

According to federal court records, Robert Lang of Warren has been sentenced to 140 months in prison followed by five years of supervised release on a charge of attempted possession with intent to distribute a controlled substance.

Lang pleaded guilty to this charge in May.

According to an affidavit filed in U.S. District Court, a security official from FedEx notified a Home Security Special Agent last October after opening a package containing toys, kinetic sand, a bag of peanuts, and a one-kilogram, shrink-wrapped brick wrapped in a towel.

According to the FedEx Terms and Conditions posted on its website, FedEx reserves the right to open and inspect any package.

An agent from the Drug Enforcement Agency said in the affidavit that the brick tested positive for the synthetic opioid, hexanoyl fentanyl hydrochloride.

The DEA says it replaced the narcotic brick with a harmless substance, spraying it with “clue spray”, a liquid that is invisible until it is exposed to ultraviolet light.

After placing a GPS tracker in the package and a device that would send a signal when it was opened, the parcel was delivered to its intended destination, a home on Clearwater Street NW in Warren.

Keeping the home under surveillance, agents say Lang picked up the package and while driving it to another address on Stephens Avenue NW, investigators got an alert that the package had been opened.

Agents called Lang out of the home and found the empty delivery box in a trash can.  In addition, according to agents, Lang’s hands glowed green under ultraviolet light from the clue spray.

The affidavit says that under questioning, Lang admitted receiving packages containing narcotics from the same sender three times before.

In addition to his sentence, the government has seized Lang's Jeep Cherokee and more than $7,000 in cash recovered during the investigation.