A teenage boy was arrested Tuesday for allegedly attacking a 71-year-old man outside a wild party in Northern California Saturday night.

The Santa Cruz County Sheriff's department announced the arrest but said it couldn't release many details because the suspect is a juvenile.

The party was at a house in Aptos, attended mostly by local high school students and teenagers while they host's parents were away.

That night a neighbor, 71-year-old Michael Mora, came out to ask some party goers to move their cars because they were blocking driveways.

A Mora family friend and neighbor said people at the scene describe a male teenager coming over and attacking Mora from behind.

"Blindsided" said Dan Garcia, "struck violently on the side of the head and then he was pushed..shoved..down the embankment. Then the assailant continued to pummel him."

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"I was absolutely disgusted," said Shauna, "I asked them what was so 'awesome' about beating up a 71-year-old."

Mora was taken to Dominican Hospital in Santa Cruz and underwent successful brain surgery.

According to his wife, Mora had been in critical condition but is now in stable condition and undergoing rehabilitation sessions.

Santa Cruz County Sheriff's Deputy, Ryan Kennedy, said the 16-year-old was arrested Tuesday morning without incident and taken to the local Juvenile Hall.

"He was charged with 'assault with great bodily harm' and because of the age of the victim 'elder abuse’,” Kennedy said.

The teenager will be processed through the juvenile court system.

"I'm grateful he was arrested," said Shauna, "he should be ashamed of what he did."

"Right now we are just focusing on helping Michael recover," she added, "we are so lucky to have gotten so much support and help from friends as well as the community."