George Schmidt of Butler, PA, was a witness to an attack on a Butler police that left the officer with a knife in his stomach and the suspect dead Tuesday morning.

“I saw the policeman fall over here with a knife sticking out of his stomach. And he reached over, he reached for his gun and pop, pop, pop,” Schmidt said.

The former Marine and Vietnam veteran’s training kicked in when he saw the wounded officer. He knew not to attempt removing the knife, CBS reports.

“I took my shirt off and I put it on his wound,” Schmidt said. “He was in pain. He kept saying, ‘Oh, my God.’ He told the cops, ‘Please, call my wife.'”

“I said, ‘Sir, hang in there’ because I know he was traumatized, too. I could tell he was starting to pass out,” Schmidt added.

Police say the officer is in critical condition at UPMC Presbyterian Hospital. His name has not been released.