Two Northern Virginia friends are in hot water after one of them stole an FBI machine gun and later used the weapon to shoot at a tow truck, according to charging papers.

Jonathan Cowden, 26, a security guard and Nate Whilden, 26, a self-described music instructor, have both been charged with possession of a machine gun, a felony that carries a penalty of up to 10 years in prison.

Cowden, of Leesburg, is scheduled for a plea hearing Monday.

According to charging documents filed in federal court in Alexandria, Whilden told friends that he broke into a FBI sedan parked in his Clifton neighborhood and stole a black bag from the trunk. Inside the bag was an agency-issued Heckler and Koch MP5/10mm machine gun and a body armor vest with "FBI" emblazoned across the front, ammunition and other law enforcement equipment.

When Whilden opened the bag, he told a witness he realized he was now in possession of an FBI machine gun and thought, "Oh, crap, what did I do," charging papers said.

Cowden, who police described as an "avid collector of exotic guns," agreed to buy the weapon for "a couple grand," and both men drilled out the serial number on the machine gun, documents charge.

In November 2012, the friends were at Cowden's house in Leesburg when someone fired the machine gun and a bullet struck a tow truck, police said. It's unclear if the shooting was accidental, but neither man has been charged with the shooting.

The tow truck driver called police and Leesburg detectives issued a search warrant at Cowden's residence where they found the machine gun with the serial number obliterated and an FBI body armor vest located in a gun safe in Cowden's living room. The FBI lab confirmed that the weapon was the one taken from the special agent's car.

After police discovered the stolen gun, Whilden sent a message to a cooperating witness with the plea, "Pray for me."