I saw on the NBC site that authorities are saying a 308 caliber rifle was used. Either they are saying a 30 caliber or a 308 Winchester. The latter means they found shell casings, the former is from examining the bullets.
Another report mentioned the shots were from about 200 ft, not exactly long range for a rifle.
A law enforcement official, speaking on the condition of anonymity, told the Associated Press that an arrest warrant would be issued soon. Philadelphia TV station WPVI is also reporting that officials say they know the suspect's identity, and that a Jeep found in a swampy area near the shooting may be connected.
Meanwhile, state police obtained a search warrant in Monroe County overnight in connection with the ambush.
Magisterial District Judge Michael Muth, whose district encompasses East Stroudsburg, confirmed he issued the warrant, but declined to release a copy or provide specifics of what or where police planned to search.
http://www.mcall.com/news/breaking/mc-pa-state-trooper-ambush-warrant-20140916-story.html