Woman wielding bike helmet stops sexual assault in Philadelphia

PHILADELPHIA -- Police are searching for a man who they say sexually assaulted a 63-year-old woman Monday afternoon in Philadelphia.

Mary Martin said she used her voice and her bike helmet to intervene and stop the assault in progress.

"I was really mad. He was casually walking away as she was really upset," Martin said.

Martin said she refused to let the man get away.

"We just want to make sure whoever this guy is, is identified," she said.

SEE ALSO: 'I was going to fight': Woman recalls creepy encounter with man wearing Chucky mask in Philadelphia

Police released photos Martin snapped of a suspect running from the scene after the alleged assault, which happened around 4:15 p.m. in the city's Point Breeze neighborhood.

A witness described seeing a woman chasing the man.

"A woman was running after the suspect with her bike helmet and saying, 'How dare you? How dare you?" the witness said.

Martin said she stepped in after seeing how shaken the victim was.

"When I saw her face and how upset she was, I was really mad that someone would do that to someone. I was holding my bike helmet, so I started hitting him with it," she said. "I realized, 'You're putting yourself in an unsafe situation.'"

So, she then took photos of the man and returned to check on the victim.

Martin provided the photos to detectives.

She credits training and learning about the harmful 'bystander effect' for spurring her into action.

"If you see something, say something. There's a lot of power in calling out gross behavior. He didn't stop because she was yelling; it wasn't until I, outside the situation, interrupted him and said, 'What you're doing isn't OK," she said.

Martin accompanied the victim to the Special Victims Unit to make a report.

Police are still searching for the suspect.