SEATTLE (AP) - The lawyer for the father of the Washington teenager who fatally shot his classmates in a high school cafeteria in 2014 asked a federal appeals court to throw out the father's conviction for illegally possessing firearms.

John Henry Browne told a three-judge panel from the 9th U.S. Circuit Court of Appeals Wednesday prosecutors failed to prove Raymond Fryberg was served a 2002 domestic violence protection order, which would have prohibited him from possessing firearms.

Fryberg's 15-year-old son Jaylen used one of his father's guns to kill four friends and wound another at Marysville-Pilchuck High School north of Seattle.

Browne said Raymond Fryberg successfully passed several background checks, including one for a concealed-weapons permit, so he didn't know he was not supposed to have guns.

But Assistant U.S. Attorney Bruce Miyake argued Fryberg was in court in 2012 for violating the protection order, so he knew about it. Mikyake said Fryberg lied when he didn't disclose the protection order when buying his guns.