"I can't imagine a person ever getting that thought in their head that I'm going to attack a 90-year-old woman or a woman at all is just disgusting," Robb Revelli said.

But Revelli witnessed just that.

As Revelli was inside an East Oakland AM PM market buying a drink Monday morning, a man tackled and robbed the elderly woman who was on her way inside the store to ask for directions.

The attack was captured by surveillance cameras.

Revelli jumped into action. He helped the woman collect her credit cards, but what happened next was remarkable.

"I asked her if she wanted to go to the hospital or go chase this guy and she wanted to chase him," Ravelli said. "If she was down I was down to go get him and we did."

Revelli and the 88-pound senior jumped into her car and chased the suspect down.

At some point Revelli got out and caught the man as the woman called 911.

The senior told NBC Bay Area she was on her way home to the Central Valley and took a wrong turn. She had no idea she was in Oakland until she asked another witness.

The 90-year-old said she was incredibly grateful Revelli was there to help.

"He's an excellent, wonderful fellow," she said. "I hope God protects him and blesses him for the rest of his life."