DAVIS (CBS13) – Davis police are investigating a vicious attack outside a supermarket.

Good Samaritans jumped in to help save a beloved homeless woman in the community from a man who was beating her.

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Cell phone video shows a truck pulled over and a man waving down people, as the woman, brutally attacked, lays motionless nearby .

“He immediately got in front of my car and yelled ‘help, help,'” Davis resident Mark Hopkins said.

Hopkins did stop to help and described what he saw.

“When I pulled up he was punching her, stepping on her face, and I can still hear the sound that it made,” Hopkins said. “It’s not like a normal punch. It was bad.”

Hopkins first yelled at the attacker to stop then chased him away.

More cell phone video shows the suspect eventually surrounded, laying on the ground and detained by several Good Samaritans.

Cliff Sheppard was there, giving the woman something soft to lay on, until paramedics arrived.

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It was an emotional scene.

“The community,” Shepard said, “I mean the way the job was divvied up, some people were tending to Heidi.”

Heidi is the name of the 59-year-old woman attacked and now in the hospital. A beloved, familiar face on the south Davis streets.

Hopkins didn’t know it was her when he first pulled up to help. He has often given her food and clothing.

“Anybody in Davis knows who she is,” Hopkins said.

Davis police say the man Good Samaritans detained is Joseph Granken, from Placer County, and also believed to be homeless.

It was a brutal attack and a bold response from people willing to risk their own safety in a move that may have been life-saving.

Heidi is in the UC Davis Medical Center with some very serious injuries.

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Granken is in jail facing felony assault charges.