One of the four suspects in a Happy Valley home invasion last year has pleaded guilty in federal court to robbery affecting commerce and use of a firearm during the commission of a crime of violence.

Steven Acton, 27, formerly of Whitefish, entered his plea before U.S. District Court Judge Dana Christensen on Aug. 8 in Helena. Acton faces up to 20 years in prison, a $250,000 fine and an additional mandatory seven-year prison sentence for use of a firearm during the commission of a crime of violence.

According to local police reports and state court records, two armed adult men entered the Happy Valley residence on July 6, 2011, about 3:30 p.m. A 16-year-old female who was in the home at the time was held at gunpoint as the men stole a safe filled with guns.

Leads developed the next day resulted in the arrest of Kevin Gaethle, 30, Kalispell, who had the safe with him in Columbia Falls when arrested. Bradley Thompson, 26, of Kalispell, was arrested when he was caught allegedly shoplifting at Wal-Mart in Kalispell. Kelly Campbell, 22, of Columbia Falls, was arrested during a traffic stop.

Acton, who allegedly pointed a laser-sighted handgun at the girl during the robbery, was arrested by the U.S. Marshals Service in Renton, Wash., on July 19, 2011. He was also wanted for allegedly running a heroin and methamphetamine drug ring and for making counterfeit money.

Gaethle and Thompson pleaded not guilty in federal court on April 12. Both were charged with robbery. Thompson was also charged with use of a firearm during the commission of a crime of violence. Campbell has not been charged in federal court. He faces a felony robbery charge in Flathead County District Court.