Investigators searching for the "extremely dangerous" suspect who killed a Pennsylvania state trooper and wounded another during the weekend say he's a sharpshooter and a survivalist. Murder charges were filed Tuesday against Eric Matthew Frein, 31, of Conadensis, Pennsylvania, as hundreds of law enforcement personnel searched a rural, wooded area.

Frein allegedly ambushed two troopers during a shift change at the Blooming Grove barracks late Friday, killing Cpl. Byron Dickson, 38, of Dunmore. Trooper Alex Douglass, 31, was wounded. A third trooper who entered the building just 90 seconds earlier escaped injury, ABC News reported.

Frein's father, retired Army Maj. E. Michael Frein, told police that he had taught his how to shoot and that two of his weapons are missing, ABC News reported. He said his son was a member of his high school rifle team and "doesn't miss."

State Police Commissioner Frank Noonan told a news conference investigators Frein is "extremely dangerous."

"He has made statements about wanting to kill law enforcement officers and also about wanting to commit mass acts of murder," Noonan said. "What his reasons are, we don't know. But he has very strong feelings about law enforcement and seems to be very angry with a lot of things that go on in our society."

Frein is believed to be hiding in a wooded area of eastern Pennsylvania armed with a .308-caliber rifle and an AK-47. Police said he used the .308 to fire at Dickson and Douglass. A search of Frein's bedroom revealed a copy of an Army manual called "Sniper Training and Employment," the Associated Press reported.

"We have no idea where he is," Noonan said.

Lt. Col. George Bivens said Frein's anti-police views were well-known, the Wilkes-Barre Times-Leader reported.

“This was not unexpected,” Bivens said. “As we’ve interviewed a number of people, that’s been the common theme. This was not a surprise.”

A Jeep believed to have been used by Frein was found Monday slightly submerged in a swampy area by a man walking his dog. Inside were Frein's ID and shell casings, military gear, camouflage face paint and empty rifle cases, NBC News reported.

Frein is described as white, 165 pounds and 6-foot-1, with blue eyes.