A Rochester police officer did not hesitate to provide critical and life-saving medical aid to a man who was stabbed in a local library.

When Officer Nicholas Vandemar arrived at the scene of the stabbing at the Monroe Branch Library on Monroe Avenue, he quickly noticed that the victim had lost a lot of blood from being stabbed.

“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-TV. “There was a gray sweatshirt wrapped around his right bicep, and he was complaining about right arm pain.”

Police say the man, 60, was stabbed at least once in the arm with a knife outside the library at around 4 p.m.

Officer Vandemar took immediate action by taking a tourniquet from his belt and applying it to the man’s arm — a move doctors say saved the man’s life by preventing blood loss.

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

It was something the officer was trained to do.

Dr. Mark Gestring and his team at URMC Kessler Trauma Center have advocated for community training and the use of tourniquets in their Stop the Bleed program.

 “You only have to look at it once or twice to get a sense of how it works. The equipment is cheap, and it doesn’t expire. We’re trying to co-locate those things in the public, whether it’s libraries or train stations or private vehicles, so that people can have access to these things when they need them,” Dr. Gestring said.

The victim was transported to Strong Hospital, where he underwent a successful surgery.

The suspect, 18-year-old Yosmain Ammons, was arrested later that day after threatening staff at Rochester General Hospital with a knife.

Ammons was charged with assault in the second-degree and second-degree menacing at Monroe County Jail. Police say they do not believe the attack was random.