COLUMBIA, SC — A Columbia man pleaded guilty to federal gun and drug charges Tuesday, U.S. Attorneys said.

John Henry Griffin, 27, was convicted of possession with intent to distribute marijuana and of being a felon in possession of a firearm. He faces a maximum of 20 years behind bars and $750,000 in fines for the two crimes.

Griffin, attorneys said, was caught at a Columbia truck stop Sept. 22, 2011 with a .40-caliber handgun and approximately 2 ounces of marijuana. He was booked on state charges and was released from jail on bond.

Then, on Dec. 30, 2011, Columbia Police again arrested Griffin after receiving complaints of a man threatening people with a gun at an apartment complex. Officers arrested Smith at the complex and found a loaded .380-caliber handgun in his possession.

Under federal law, Griffin is prohibited from owning a gun or ammunition because he has prior state felony convictions for drug possession, gun violations and aggravated assault.

Griffin’s case was investigated by the Columbia Police Department and the federal Bureau of Alcohol, Tobacco, Firearms and Explosives. It was prosecuted as part of a joint local, state and federal initiative that focuses on firearms cases.