Michael Winter

USA TODAY

Pennsylvania State Police say they have found two pipe bombs discarded in the Pocono Mountains by the fugitive being hunted over the ambush that killed one trooper and wounded another 18 days ago.

Police spotted the suspect, 31-year-old Eric Frein, within the past 24 hours "in close proximity" to the explosives, Lt. Col. George Bivens said at a news briefing Tuesday.

Both devices were functional but not "deployed" and could have been detonated either by trip wire or fuse, he said. They were among items that Frein appears to have abandoned hastily.

Frein , of Canadensis, has been on the run since the Sept. 12 attack on the state police barracks at Blooming Grove. Hiding in the woods across the road, a sniper with a high-powered .308-caliber rifle killed Cpl. Bryon Dickson and wounded trooper Alex Douglass.

Authorities have said Frein has an unspecified vendetta against police and had expressed a desire to kill officers or commit mass murder. Bivens said nothing to indicate the troopers were targeted specifically.

Frein has been described as a survivalist, skilled sharpshooter and "military simulator" who pretends to be a Cold War-era soldier from Serbia. The FBI said he claimed to have fought with Serbians in Africa, and studied the Serbian and Russian languages.

The manhunt has focused on thick woods near his parents' home, and police said last week they considered the area to be booby-trapped based in part on evidence that Frein had experimented with explosives.

Last week, searchers reportedly had spotted Frein from a distance and found dirty diapers and empty European cigarette packs, which they surmised were discarded by Frein.

Frein is one of the FBI's 10 most-wanted fugitives, and the agency is offering a $100,000 reward for information leading to his arrest. An additional $75,000 has been pledged. But police have shoot-to-kill authority if he doesn't surrender.