CANADENSIS, Pa. (AP) -- Authorities say they are taking "extreme precautionary measures" as they search a heavily wooded region of northeastern Pennsylvania for the suspect in last week's deadly ambush at a state police barracks.

State police spokeswoman Maria Finn says troopers are determined to find 31-year-old Eric Frein (freen) and bring him to justice.

Police are focusing their search on the neighborhood where Frein lived with his parents in Pennsylvania's Pocono Mountains. A shelter-in-place order was in effect Saturday for two townships near Canadensis, about 100 miles north of Philadelphia.

Police surround a neighborhood in the Pocono Mountains in search of suspect Eric Frein on Saturday, Sept. 20, 2014 in Canandensis, Pa. (AP Photo/Chris Post)
Police surround a neighborhood in the Pocono Mountains in search of suspect Eric Frein on Saturday, Sept. 20, 2014 in Canandensis, Pa. (AP Photo/Chris Post)
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Police say Frein fatally shot one trooper and wounded a second with a high-powered rifle on Sept. 12. He has been described as a self-taught survivalist with a grudge against law enforcement.

Authorities who spent the night in the neighborhood donned bulletproof vests and gathered heavy rifles before fanning out Saturday morning.

The burst of activity followed a long night that included reports of gunfire and police telling residents to stay in their homes.

Police have been largely silent about the details of their search, including how big of an area they are combing, whether they have the suspected shooter surrounded or how much longer it will be before residents can move about freely.

Authorities Friday night closed roads in the wooded neighborhood of Barrett Township, in the Pocono Mountains, as they searched for 31-year-old Eric Frein, described as a self-taught survivalist with a grudge against law enforcement and government.

Gunfire was reported around 6:40 p.m., a Monroe County 911 dispatcher said. Authorities have not discussed that report, including if there were any injuries.

State police told residents in the townships of Price and Barrett to stay inside and asked others not to travel to the area because of heavy police activity. Some who had been kept away were allowed to return to their homes Saturday morning, but told to shelter in place.

Shortly before noon, resident Joe Ksiaskiewicz tried to pass through a roadblock to get home, but was stopped by officers.

Ksiaskiewicz said the officers told him it was a "critical time" and would not let him pass. He had hoped to get through to be with his 27-year-old daughter, Ellen, who was stuck at home while he and his wife spent the night with their older daughter because they couldn't enter their neighborhood.

"She's ready to be done," Ann Winner said of her sister. "She's been listening to helicopters all night."

Al and Debbie Mundy spent the night in their pickup after going out for groceries Friday night. When they got to the end of the road, a state trooper told them they would not be permitted back into the neighborhood.

"They would not let us turn around to go a quarter-mile back to our house," Al Mundy said.

An unmarked helicopter flew overhead early Saturday, its lights off. After daybreak, two FBI agents in a black SUV donned tactical gear before heading toward the search area.

Police have charged Frein with opening fire outside a state police barracks in northeastern Pennsylvania on Sept. 12. Cpl. Bryon Dickson was killed and Trooper Alex Douglass was wounded by a gunman with a high-powered rifle.

Frein has been on the run ever since. He was placed on the FBI's 10 most wanted list, and hundreds of law enforcement officials have been searching for him in the dense woodlands surrounding his home in Canadensis. Schools in the area were closed again Friday.

Canadensis resident Richard Barry couldn't get home from work Friday night before the roadblocks went up. Barry said Saturday morning that he heard from family members who were at home and they told him police were going through their yard and the dog was barking.

Worried about his family, he said he preferred to wait near police in hopes of hearing something rather than staying overnight at the firehouse.

"I'm hoping that sooner or later he (Frein) just says `I give up. You win,'" Barry said.

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