A Rochester, NY, police officer is credited with using his tourniquet to save the life of a 60-year-old man who was stabbed in the arm Tuesday at a local library.

Officer Nicholas Vandemar entered the library, saw blood on the floor, and then a man crumpled up against the wall. He had been stabbed once in the arm.

“I could tell by his condition, and just by how out of it he was that he had lost a lot of blood,” Vandemar told WROC. “There was a gray sweatshirt wrapped around his right bicep and he was complaining about right arm pain.”

Vandemar grabbed the tourniquet off his belt and tied it around the man’s arm. Doctors later told the officer his actions prevented the man from bleeding out.

“That’s when I started to digest how serious it was and how vital or lucky that things just worked out perfectly,” Vandemar said