Report: Frein letter detailed trooper ambush plan

As their manhunt for Eric Frein entered a fourth week, police on Monday declined to comment on a report that they found a handwritten note from the accused shooter.

Citing unnamed sources, CNN reported that investigators found a letter they believe was written by Frein that detailed his alleged Sept. 12 shooting of two state troopers and Frein's escape into the woods. The news station did not say where investigators found the letter or when it was written.

The state police declined to confirm or deny the claim. "I am not commenting on any evidence found unless it poses a threat to the community," Trooper Tom Kelly said in a statement.

Frein is charged with killing Cpl. Bryon Dickson and wounding Trooper Alex Douglass at the Blooming Grove barracks.

More than 1,000 officers have participated in the search for Frein, a self-styled survivalist who police say they believe has been hiding in a five-square mile area near his family's Monroe County home.

He was sighted as recently as Sunday afternoon, police said, but has continued to evade capture in the dense woods.

Investigators hope to soon get more help - from Mother Nature. A rainy forecast could clear the leaves from treetops and allow for aerial surveillance. And temperatures are slowly dropping each night.

"The cold will help us," said Edward J. Hanko, the special agent in charge of the Philadelphia division of the FBI, which has been dispatching tactical teams to assist state police with the manhunt. "He's out there, and he's not going to be starting fires to keep warm."