-- State and federal authorities seized 14 kilograms of the potentially lethal opioid fentanyl in a Camden drug sweep on Thursday, according to the New Jersey State Police.

They also charged a city man, Yahmire Boardley, for allegedly possessing and selling the drug, which authorities say has caused a spike in deaths among users of heroin and prescription painkillers.

Fentanyl is a powerful opioid - up to 50 times more powerful than heroin - that is prescribed to cancer patients and others with longterm, serious illnesses, but in recent years has found its way onto the street, where it is cut into other drugs to increase their potency.

Because it is colorless and odorless, it's also difficult for the casual drug user to detect.

On Thursday, authorities say a team of local, state and federal police who had been working on a month-long investigation executed search warrants around Camden, seizing the drug from locations around the city.

Col. Rick Fuentes, the head of the State Police, said the "massive seizure of fentanyl, which is a highly addictive and lethal opioid, almost certainly saved lives."

Boardley, 22, was charged with possession of a controlled dangerous substance and possession of a controlled dangerous substance with intent to distribute. It was not clear how much of the drug he was personally accused of possessing.

He was being held Friday at the Camden County Jail pending a bail hearing.