Accused cop-killer Eric Frein has been spotted with a rifle near a Pennsylvania high school Friday, NBC reported.

Frein has evaded authorities for a month, since killing a Pennsylvania State Trooper, despite an active manhunt during that time frame.

More than 1,000 officials have been actively searching since the Sept. 12 ambush on the Blooming Grove barracks, and Frein is on the FBI Most Wanted list.

"We had a sighting for which we are assigning a high level of credibility," State Police Lt. Col. George Bivens told reporters Saturday, NBC reported.

The witness who reported the sighting was not able to positively identify Frein but described an individual in great detail that matched Frein's description, police said.

The witness was less than 20 feet away from him near the campus of Pocono Mountain East High School, which Frein attended.

"Everybody has one mission, and that mission is to apprehend this individual," Pennsylvania Gov. Tom Corbett told NBC.

Other witness reports indicate blood on patios in the area, and tests are underway to see if it is blood and if it is Frein's.

Following the shooting of Cpl. Bryon K Dickson II and wounding of Trooper Alex T. Douglass, there have been signs of Frein's presence in the Pike and Monroe county area, but no one has yet captured the alleged murderer.

Police have said the 31-year-old is a survivalist and may have had pipe bombs, food packs and clothing with him.

The manhunt in the region delayed the hunting season in the Poconos this year, in order to keep the area clear for sightings of Frein.

Authorities have said that though it is taking time, they are sure that Frein will soon come out of hiding.

Greg Hall, a former Pennsylvania State Police supervisor, told NBC, "This guys is not Jason Bourne. Once he gets incredibly uncomfortable, he will give it up or precipitate a fight. Time is on the authorities' side because the weather is degrading and his supplies are degrading. But right now, he is in control."