A convicted felon who was operating a marijuana grow house in San Leandro has been sentenced to more than six years in federal prison for his conviction on illegal drug and gun charges, prosecutors said Friday.

Vincent Nguyen, a 21-year-old Oakland man, received a 78-month sentence after he pleaded guilty last October to conspiring to possess with the intent to distribute marijuana, possessing with the intent to distribute marijuana, and being a felon in possession of firearms, according to U.S. Attorney Melinda Haag.

Authorities said Nguyen, who had previously been convicted in 2010 for felony possession of marijuana for sale, was arrested on Jan. 10, 2012, after complaints from citizens led to an investigation by San Leandro police and the FBI.

He was later indicted, along with others, by a federal grand jury on June 7, 2012.

Prosecutors said that in his plea agreement, Nguyen admitted that from August 2011 through January 2012, he and others operated a marijuana grow house at 3471 Carrillo Drive in San Leandro.

Nguyen was found in possession of 82 mature marijuana plants, nearly one kilogram of marijuana packaged for sale, a Norinco US 7.62-caliber rifle with a high capacity magazine, a Romak-Romarm 7.62-caliber assault rifle that had been stolen and a .45-caliber Smith & Wesson semiautomatic pistol, according to prosecutors.

In addition, about $10,000 in cash, a 9mm Bryco Arms semiautomatic pistol and more than 100 rounds of various ammunition were found at the grow house and seized by law enforcement officers, prosecutors said.

U.S. District Court Judge Phyllis J. Hamilton sentenced Nguyen to three years of supervised release after he serves his 78-month prison term.

Co-defendants Van Do Nguyen and Loc Huynh were sentenced by Judge Hamilton on Jan. 23 to 72 months and 87 months in prison, respectively.