Image copyright AP Image caption Frein is the key suspect in the attack

Police in Pennsylvania have identified a suspect in the killing of one officer and the wounding of another on Friday.

The suspect has been named as Eric Matthew Frein, 31, from Canadensis.

Around 200 officers are searching for Mr Frein, who police say has expressed a desire to kill law enforcement officers and commit mass murder.

He is described as armed and "extremely dangerous" after opening fire with a .308-caliber rifle outside the Blooming Grove state police barracks.

Captain Bryon Dickson was killed outside the barracks in north eastern Pennsylvania during a shift change on Friday evening.

State Trooper Alex Douglass was critically wounded in the attack.

Police sources said Mr Frein's jeep was later found in a swampy area near the barracks.

A judge has issued an arrest warrant for Mr Frein who was described as armed and "extremely dangerous" by Mr Noonan.

Image copyright AP Image caption Police say Captain Bryon Dickson was killed by a man who has hunting or firearms experience

The motive for the attack is unknown, but police said it is likely the gunman had a grievance against the state police.

Earlier police released a profile of the attackers, saying he could be an avid hunter or have received firearms training from the military or police.

It also said the attacker likely made regular visits to a shooting range to keep his skills sharp, as well as trip to the barracks to plan his attack.

A non-profit group has offered a reward of $75,000 (£46,000) for information leading to the gunman.