A Forestville man with three previous drug convictions was sentenced to 20 years in prison Thursday for possessing and conspiring to distribute PCP, authorities said.

Marvin Antoin Duckett, 39, was long a target of narcotics detectives. Authorities said that during a 17-month investigation, police seized 283 ounces of liquid PCP, 5.6 grams of cocaine, two handguns and a Mercedes Benz from him or his associates.

In July 2009, investigators seized 421.4 grams of a PCP mixture and $10,115 from an Upper Marlboro home Duckett used, authorities said. Then, from July through September of that year, an undercover officer bought PCP from Duckett six times through a co-conspirator, Troy Orlando Tongue, authorities said.

In total, authorities said, the officer bought 292.9 grams of a PCP mixture, valued at $9,900.

In April 2010, a U.S. Park Police officer stopped Duckett and found more than 400 grams of PCP, authorities said. Duckett and another co-conspirator, Travis Lamont Armstead, were also flush with cash; investigators seized $1,400 from Duckett and $901 from Armstead, authorities said.

Duckett pleaded guilty to his drug-related crimes, and investigators believe he is responsible for distributing at least one kilogram of a PCP mixture, authorities said. His sentence was increased because he has three previous drug convictions, and a federal judge deemed him a career offender, authorities said.

Tongue, 36, of Shadyside, Md., and Travis L. Armstead, 29, of Petersburg, Va., also pleaded guilty to their participation in the conspiracy. Armstead was sentenced to three years in prison, and Tongue is awaiting his sentence.

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