BLOOMING GROVE, Pa. >> Hundreds of law enforcement officers fanned out across the dense northeastern Pennsylvania woods Tuesday in the hunt for a heavily armed survivalist suspected of ambushing two troopers as part of a deadly vendetta against police.

Eric Matthew Frein, 31, of Canadensis, is "extremely dangerous" and residents in the area should be alert and cautious, State Police Commissioner Frank Noonan said at a news conference in which he revealed the suspect’s name.

"He has made statements about wanting to kill law enforcement officers and also 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 was charged Tuesday with first-degree murder, homicide of a law enforcement officer and other offenses. About 200 law enforcement officials were combing the rural area of northeastern Pennsylvania marked by dense forest, but "we have no idea where he is," Noonan said.

Police found a U.S. Army manual called "Sniper Training and Employment" in the suspect’s bedroom at his parents’ house, and his father, a retired Army major, told authorities that his son is an excellent marksman who "doesn’t miss," according to a police affidavit released Tuesday.

The gunman killed Cpl. Bryon Dickson, 38, and critically wounded Trooper Alex Douglass outside the remote post in the Pocono Mountains during a Friday night shift change, then slipped away.

Authorities zeroed in on Frein after a resident who was walking his dog in a wooded area two miles from the barracks Monday spotted a 2001 Jeep partly submerged in a pond and called 911. Police found shell casings inside the vehicle that matched those found at the shooting scene, Noonan said.

Investigators also found Frein’s driver’s license, Social Security card, a Pennsylvania Game Commission range permit, camouflage face paint, a black hooded sweatshirt, two empty rifle cases, military gear and information about foreign embassies, according to court documents.

Frein has held anti-law enforcement views for many years and has expressed them both online and to people who knew him, Lt. Col. George Bivens said.

Frein’s father, Michael Frein, who spent 28 years in the Army, told police that two weapons were missing from the home — an AK-47 and a .308 rifle with a scope, according to the police affidavit.

Two state police troopers armed with rifles stood in the driveway of the home, a well-kept two-story in a private community, and several cars were parked there Tuesday afternoon.

With the gunman still on the loose, residents were jittery. Rich Turner, 52, who lives around the corner, said school buses avoided the neighborhood Tuesday, with parents directed to take their kids to school and to pick them up. All schools in the Pocono Mountain School District will be closed Wednesday because of safety concerns.

"Everybody’s wondering if he’s still out there. Everyone’s on edge, to a degree," said Turner, who didn’t know Eric Frein but said he had dealings with his mother, who headed the community association.

Lars Prillaman, who manages a small farm in West Virginia, said he knew Frein briefly from their time as military re-enactors. He told The Associated Press he was "saddened by what happened" and that Frein was "a different person eight years ago."

Prillaman told NBC News that he and Frein were involved in a World War II "living history" group and played Germans, but the group did not permit any neo-Nazis.

"I can’t begin to imagine what would have caused someone like him to go down this path," he told NBC.

Court documents filed Tuesday revealed heartbreaking new details about the ambush. According to the documents:

Dickson was shot as soon as he walked out the front door of the barracks. A communications officer heard the shot, saw Dickson on the ground and asked him what had happened. Dickson told her he’d been hit and asked her to bring him inside — but the gunman had squeezed off another round, forcing his would-be rescuer inside.

Douglass, meanwhile, had just arrived at the barracks and was shot in the pelvis as he walked toward Dickson. Douglass managed to crawl into the lobby, where another trooper brought him into a secure area of the barracks. Douglass later underwent surgery at a hospital.

Other troopers drove a patrol SUV into the parking lot and used it as a shield so they could drag Dickson into the barracks and begin attempts to save his life.

He died at the scene. A coroner said he had been shot twice.

About 90 seconds had elapsed between the first shot and the fourth and final one.

Michael Rubinkam and David Porter / Associated Press. Rubinkam reported from northeastern Pennsylvania. Sean Carlin in Philadelphia contributed to this report.