Police are calling a home invasion suspect armed and dangerous because they believe he stole a military-style assault rifle and some grenades in McKees Rocks.

Allegheny County police have charged Cameron Russell, 22, with robbery, burglary and other crimes in the break-in at a home along Gardner Street about 7 p.m. Monday.

Police believe Russell stole a Bushmaster M4 assault rifle, eight loaded magazines, and may also have a fragmentation grenade and several smoke grenades.

"It's obvious; they're extremely dangerous in anyone's hands," said McKees Rocks Police Chief Robert Cifrulak. "We don't know what he's capable of. We don't know what the intention to stealing this rifle was."

Police said Russell, of Pittsburgh, is known to frequent the nearby suburbs of Bellevue and West View.

Channel 11's Brittny McGraw reported that the weapons belong to a former Marine. Parker Gresh, a former marine, said he had met Russell in the past.

"That's not the type of people I want around my house. That's not the type of person I am, and I hope they go to jail for a long time," said Gresh.

Gresh said he had met Russell through a relative's friend and had him over to his house once.

"I showed him my assault rifle. It's a fun thing to show. I'm pretty proud of it. I paid $1,500 for it. It's cool," said Gresh.

Investigators said Russell returned to Gresh's home on Monday night while he was gone and threatened his girlfriend before stealing the gun and grenades.

"For him to do that to a 130 pound girl is just shameful," Gresh said.

Police charged Russell late Monday and said they were still searching for him Tuesday morning.