Police shifted their search and a northeastern Pennsylvania school district tightened security amid another reported sighting Monday of the suspect in a deadly state police ambush. A local law enforcement official reported seeing suspect Eric Frein near the Swiftwater Post Office in the Pocono Mountains, leading to an intensive police search. Frein had not been captured, Trooper Connie Devens said Monday night. The post office is near Pocono Mountain East High School, where a woman out for a walk Friday night spotted a rifle-toting man with a mud-covered face police believe was Frein, who has remained on the loose for more than a month despite the intense manhunt. Frein, 31, is charged with opening fire outside the Blooming Grove state police barracks on Sept. 12, killing a trooper and seriously wounding another. Authorities had been searching for him in the woods around his parents' home in Canadensis but shifted their primary search area 5 or 6 miles to the southwest after Friday night's sighting. Lt. Col. George Bivens said over the weekend that police have put a "tremendous amount of pressure on him" and likely forced him to move. The high school, Frein's alma mater, and all other schools in the Pocono Mountain School District were open Monday but took extra precautions in light of the Friday sighting. Additional officers from the Pocono Mountain Regional Police Department were stationed at the district's Swiftwater campus to supplement the lone police officer who normally patrols that location, which, besides the high school, includes a junior high and elementary school. Pennsylvania State Police did not recommend that schools close, district spokeswoman Wendy Frable said. "We would not bring the students in if we did not have reassurance from police they felt the campus was safe," she said Monday morning. Hours later, as police ramped up their search efforts in the area in response to the latest possible sighting, district officials moved outdoor after-school athletic practices to another campus. And late Monday, the district posted on its website a statement saying students will remain inside on Tuesday. The statement said Superintendent Elizabeth Robison spoke Monday night to a state police official who "expressed his commitment to student safety and assured her that he will notify her immediately if he ever has a safety concern for any of our schools or campuses." State police have said they believe Frein, a self-taught survivalist, has a hatred of law enforcement and wants to target police, not the general public. State police said Monday that blood found at two homes in the search area is not linked to Frein. DNA testing ruled out any link to Frein in blood droplets found on a covered porch in the area. Material found on a back door at a second home near the first turned out not to be human blood. Police believe Frein could be breaking into vacant cabins or vacation homes to look for food or take shelter.