Investigators testing rifle found in Eric Frein arrest Accused killer Eric Frein is escorted by police out the Pike County Courthouse after his arraignment in Milford, Pa., Friday Oct. 31, 2014. AP Photo/Rich Schultz SCRANTON, Pa. -- Pennsylvania State Police Commissioner Frank Noonan says investigators are testing a .308 caliber rifle recovered from an abandoned airport hangar to determine if it is the weapon used to kill a trooper and critically wound another officer in the September ambush on a police barracks. The Scranton Times-Tribune also reports that Noonan said law enforcement agencies may have had to change their strategy if the search for 31-year-old suspect Eric Frein had gone on for years. Frein was captured Thursday by federal marshals near the hanger following a seven-week manhunt in the Pocono Mountains. He is charged with first-degree murder in the Sept. 12 ambush that killed Cpl. Bryon Dickson and wounded Trooper Alex Douglass outside the Blooming Grove barracks. Prosecutors plan to seek the death penalty. Noonan told The Sunday Times in an exclusive interview that he is grateful the search didn't drag on for years as did, for instance, the five-year effort in North Carolina to find Eric Robert Rudolph, who was later convicted of the 1996 Olympic Park bombing. "We were never going to stop, but we might have changed strategies," Noonan said. We might have scaled back manpower. We were always convinced he was in those woods. We didn't want to let him regroup.... We could not leave that man out there to kill again. Noonan said the estimated $10 million cost of the manhunt includes overtime, lodging for out-of-town police and fuel for aircraft used in the search in Monroe and Pike counties. And the estimate is growing as the police work continues. "The investigation never stops until we have a verdict," Noonan said.