The man accused of ambushing two Philadelphia police officers, killing one and wounding another, now faces federal charges. Eric Lewis, 35, is accused of fatally shooting Philadelphia Police Officer Shane Seiber and wounding his partner. He faces a range of state charges, among them murder, homicide of a law enforcement officer, attempted murder, 10 counts of attempted homicide of a law enforcement officer, aggravated assault, terroristic threats and other related offenses.

In addition to the state-level charges, Lewis on Thursday was indicted on federal charges of interstate commerce by robbery, discharging a firearm during a crime of violence, possession of a firearm and ammunition by a felon, theft of a firearm that has moved in interstate commerce, and possession of a stolen firearm and stolen ammunition.

If convicted, the charges bring a statutory maximum of life in prison and a minimum of 10 years.

At a news conference on Thursday, David Metcalf, U.S. Attorney for the Eastern District of Pennsylvania, said that Lewis wasn't allowed to carry a gun under U.S. law.

"Under federal law, Eric Lewis is not allowed to possess a firearm. He is a convicted felon under federal law. He is certainly not allowed to steal a firearm, and under federal law, he is certainly prohibited from using any firearm to rob, shoot, and kill a police officer, as a result of those actions," Metcalf said.