Eugene DeRose was driving by when he spotted a police officer in a fight with a much bigger man.

"I didn't even think, I just reacted," DeRose said. "Because I knew if I didn't do anything at that moment, it would have become a lot worse. I was running on pure adrenaline."

DeRose was driving home from work last Wednesday when he saw a man attacking an Edmonton police officer near the corner of 111th Avenue and 95A Street.

He stopped in the middle of the road and got out, ran over and grabbed the man and held him until the officer could make his arrest.

A bystander shot this video of a Good Samaritan coming to the aid of a police officer trying to make an arrest. 1:25

Const. Sasa Novakovic got the chance to thank the Good Samaritan on Wednesday during a special ceremony at police headquarters.

Novakovik said on the day of the arrest, he first approached the suspect and his female companion after watching them jaywalk across the busy intersection.

But what started out as a routine bylaw warning quickly escalated into something much more dangerous.

"From the onset, the male subject was not co-operative, continually yelling at and walking away from me," Novakovic said. "Once I attempted to arrest the subject, he became combative, charging at me with his fists. We fought standing, until we ended up on the ground."

The police officer said he was pinned to the ground while the woman fled the scene.

"Once on the pavement, the 280-pound subject ended up on top of me, with most of his weight on my chest," Novakovic recalled. " With one of my arms pinned, I tried to gain control. But not being able to breathe, my options were getting limited."

That's when Derose sprang into action.

"He jumped out his vehicle and placed the subject in a headlock. He did so without hesitation," said Novakovic, who is nominating DeRose for a Citizen Award. "It's very important to me that Eugene is recognized for what he did that day."

The pair shook hands during a recognition ceremony at police headquarters on Thursday morning.

"Every day, police risk their lives for strangers," said Novakovic. "It's the job we chose. But on Feb. 17, it was a stranger who risked his life for the police. And my family and myself are truly thankful."