The homeless son of a former New York City detective is being called a hero after he stepped in to help a San Francisco cop who was being attacked by a suspect.

The incident occurred Monday night, when a female officer came upon a woman who allegedly was vandalizing cars by jumping up and down on them, San Francisco Police Department Sgt. Eli Turner told ABC station KGO-TV.

The officer, who was alone, tried to calm the woman down, but she only became more agitated and eventually attacked the cop, Turner said.

A crowd formed, but even though the officer called for help, no one did anything until Ryan Raso jumped in as the suspect started to grab for the cop's gun. He wrestled the woman to the ground and held her until other officers arrived, police said.

But when police wanted to thank the man who'd come to the aid of one of their officers, they couldn't track him down, until Friday.

Raso, 35, had a simple explanation for what he did.

"An officer was being beaten up, a human, so I did what was right," Raso said.

"The person had the officer kind of like in a choke hold and was kind of had her … had the officer against the wall kind of banging her kind of beating her I think her head against the wall a little bit," he said.

"A law enforcement officer is saying, 'help me, help me' when there's no one else around doing anything," Raso said.

Police said they would try to find shelter for Raso and they bought him new headphones, since his were broken.

"He has been homeless; he's had a rough time in recent months," Turner said. "We wanted to reach out to him and let him know he has friends."