BLOOMING GROVE TWP., Pa. -

A multi-state manhunt is on after one or more gunmen opened fire on a Pennsylvania State Police barracks in the Poconos.  One trooper was killed and another is in stable but critical condition at a Scranton hospital.

State Police said Sunday that the reward for information has been upped to $50,000.

The attack happened just before 11 p.m. Friday at the State Police barracks in Blooming Grove, Pike County, just off Interstate 84 near Lake Wallenpaupack.

"It's a cowardly attack," said PSP Commissioner Frank Noonan.  "It's an attack upon all of us in society."

State Police identified the deceased trooper as Cpl. Bryon Dickson of Dunmore. Trooper Alex Douglass was injured.  Investigators said the two were ambushed in the barracks parking lot at a shift change.  One trooper was leaving and another was just reporting to work, according to Noonan.

"This attack was an ambush," the commissioner said.  "Our troopers were leaving the barracks and were shot without warning, and really had no chance to defend themselves."

Dickson was a seven year State Police veteran who recently transferred to the Poconos from Philadelphia.  Douglass joined in 2005 and once served in the Reading barracks.  Investigators aren't sure if the two were specifically targeted or just in the wrong place at the wrong time.

"We're considering all of those options, but we have not come to any conclusions," said Noonan.

Saturday morning, State Police confirmed they were interviewing a "person of interest," but Noonan stressed that there are no suspects at this time and that an armed dangerous criminal is still on the loose.

"The Pennsylvania State Police and law enforcement in general will not rest until this individual is apprehended," he said.

Police across the whole region are on high alert tonight for another attack.  Noonan said every State Police barracks and local department in eastern Pennsylvania has been warned to be extra vigilant.

Anyone with information on the shootings is asked to call 1-866-326-7256.