Eric Frein, the military enthusiast wanted for killing a Pennsylvania state trooper and seriously wounding another, conducted extensive Internet searches on how to survive in the wild and elude police manhunts, state police Lt. Col. George Bivens said Friday.
"We are convinced that Eric Frein has been planning this attack at least for a couple of years," Bivens said at a news conference. "This information is supported by a search of a computer hard drive."
Frein's research also included various law enforcement technologies, Bivens said. The Internet searches were conducted on "a computer that did not belong to him, but it was one he had access to," Bivens told reporters.
"It did give us a lot of insight into some techniques he might be employing [and] it gave us some insight about what his escape might involve," said Bivens.
Bivens declined to discuss who owned the computer or how Frein was linked to it.
"He did have his own computer and my understanding is he removed the hard drive prior to this crime," Bivens said.
Frein, a military enthusiast with extensive training as a marksman, has been the subject of a massive manhunt for the Sept. 12 shooting of Pennsylvania state troopers Alex Douglass and Bryon Dickson. The troopers were ambushed during a shift change outside the Blooming Grove barracks in northeastern Pennsylvania. Dickson was killed.
Frein, 31, faces charges of homicide of a law enforcement officer and attempted murder, police said. He also is wanted on federal charges of unlawful flight to avoid prosecution.
The manhunt has involved more than 1,000 members of law enforcement, Bivens said. It has centered in the area around Canadensis, a town of less than 3,000 residents, where Frein lived. Police are combing through dense forest, which may be giving the fugitive cover.
"There is nothing in our investigation that indicates Frein has left the area," Bivens said. "I suspect he wants to have a fight with the state police, but I think that involves hiding and running, since that seems to be the way he operates."
Bivens said authorities believe Frein has a radio with him, which he may be using to listen to broadcasts about the manhunt. The lieutenant colonel also said records indicate Frein purchased items prior to the shooting that are typically used in the construction of bunkers.
"We are aware of some purchases he made and those have been thoroughly investigated," Bivens said.
Bivens added, "We have not located that bunker."
On Wednesday, authorities said Frein has been spotted in the woods several times since the shooting and has left a trail of empty cigarette packs and dirty diapers. The discoveries have earned Frein the moniker, "Diaper Sniper' and the creation of hashtag #DiaperSniper on Twitter.
On Friday, Bivens said it has been more than 48 hours since Frein was last spotted by law enforcement.
While acknowledging the search for Frein has been challenging, Bivens said authorities will not back down.
"You are a coward," Bivens said in a direct appeal to Frein. "We are not intimidated. We will not leave ... We have a clear mission with specific objectives ... We will find you and we will bring you to justice."