A woman walking at about 9 p.m. last night is believed to have encountered accused trooper shooter Eric Frein near Pocono Mountain East High School, police say.

Pennsylvania State Police Lt. Col George Bivens said the woman saw a man dressed in dark clothing, with what appeared to be mud smeared on his face, near the wood line just off a road, but not on campus. The man was about 15 or 20 feet away, he said, and the woman provided "great detail.""The individual's description was consistent with Frein, and he was carrying a rifle. The individual's face was covered with mud, and so a positive identification could not be made. A search of that area is ongoing as we speak," Bivens said at a 1 p.m. news conference Saturday."We know Frein is familiar with this area," he said. "He attended Pocono Mountain East High School, he also worked briefly at Sanofi-Pasteur, and worked several summers at Camp Minsi, which is just to the west of that area."Police are "assigning a high level of credibility" to the sighting, he said.Bivens would not reveal exactly where the encounter took place. He said police have been talking with school officials, and have a strong presence around the school. It is not known whether classes will be held Monday in light of the sighting.Also, the owners of two homes in the Cresco area reported what they believe to be blood in enclosed back porches. Police are testing the substance, Bivens said. One sample was identified as blood, but its source is not yet known.The search area has shifted slightly south, focused in the Swiftwater area, in Paradise and Pocono townships, Bivens said.State Police commissioner Frank Noonan, accompanied by Gov. Tom Corbett, also spoke at the news conference. Both thanked police, residents, businesses and the Red Cross for their patience and support.The hunt for Frein, estimated to have cost millions of dollars, entered its 36th day Saturday. More than 1,000 law enforcement officers have been combing the woods in Barrett and Price townships. But the search has stretched beyond that area, even into other states, Bivens said.Police believe Frein, 31, shot Cpl. Bryon Dickson and Trooper Alex Douglass outside the Blooming Grove barracks in Pike County during a shift change at 10:50 p.m. Sept. 12. Dickson died, and Douglass, who was seriously wounded, was recently released from the hospital.Police have yet to determine a motive for the shootings, although Frein is said to be an expert marksman who was obsessed with portraying soldiers and held a grudge against police.Frein, 31, is said to have hidden in the woods across from the barracks to launch the ambush attack, which police say he had planned for years.Frein's computer hard drive revealed he'd searched for ways to evade police and what techniques and technology law enforcement would likely use to track and capture perpetrators.Searches of the woods surrounding the Candensis home where Frein lived his parents have netted makeshift campsites, a journal police believe is Frein's in which he detailed the night of the shootings, and personal belongings, including a rifle, ammunition, food and a sleeping bag police say Frein dropped as he fled police.Police also believe the rapid dropping of leaves will give Frein less cover, and the cold weather will drive him to seek shelter.