The husband of a 36-year-old Leesburg woman who disappeared under suspicious circumstances has been arrested on federal gun charges after investigators said he tried to hide a submachine gun shortly after she vanished.

Leyla McCullagh and Matthew Ryan McCullagh, 33, had a contentious relationship. She was arrested on domestic assault charges for an April 2012 incident in which police said she kicked in their bedroom door and threw a TV at her husband before attacking him. She accused her husband of having an affair.

She was placed on probation but failed to show up for court, and was reported to have been last seen on Aug. 14. The Loudoun County Sheriff's Office said then that it suspected "foul play."

There are new developments.

According to federal court papers made public last week, McCullagh hid a .45-caliber Thompson submachine gun from authorities as they were investigating "the disappearance and suspected homicide of Leyla McCullagh."

FBI officials have recovered the weapon, and last week McCullagh was charged with unlawful possession of a machine gun. He faces a maximum penalty of 10 years in prison. He was ordered held pending pretrial hearing.

He has not been implicated in his wife's disappearance.

According to charging documents, on the night detectives were executing a search warrant at his girlfriend's home in Herndon, McCullagh hid the weapon in the trunk of his girlfriend's car.

McCullagh told his girlfriend that he needed to stash the weapon because it was not registered or was not in good standing, documents said.

McCullagh then asked a co-worker at a business in Ashburn to hold onto the submachine gun, documents said. He told the co-worker that Loudoun County detectives had seized several of his firearms and he did not want to lose all his guns.

The friend agreed to take the submachine gun, but grew concerned that McCullagh was the subject of a criminal investigation. He called another friend who knew someone at the sheriff's office.

On Sept. 3, the detective in charge of the disappearance took custody of the submachine gun. The weapon was entered into evidence and was later sent to the FBI lab for examination. The weapon was fully functional.

According to search warrants, Leyla, a belly dancer and mother of one, had bruises on her arms and told co-workers that her husband threatened to have her deported. She told friends she was from Russia.