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.

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.