Additional details have been released on the disturbing case of a driver surrounded and beaten by motorcyclists during an illicit sideshow on a San Francisco freeway, including first-hand reports from witnesses to the attack.

You likely saw the story Thursday: A man driving a white Toyota Corolla on southbound 101 near the Cesar Chavez exit a little after 6 Wednesday evening bumped/was bumped by a motorcyclist involved in a sideshow on the freeway.

A car which appeared to be part of the sideshow effort pulled in front of the Corolla, forcing it to stop, as the bikers surrounded the vehicle. When the driver attempted to get out of the car, he was badly beaten, left with a broken leg before the members of what KRON 4 reports is "a known local bike gang" fled.

Thursday evening, the Chron reported that the driver is a 35-year-old Modesto resident named Alex, who "comes to San Francisco almost every day to drive for Uber" and is the father of a baby boy.

“He’s a good guy. He’s not a troublemaker or nothing like that. I don’t understand why someone would beat him up,” his sister told the Chron,

The attack was captured on video by a witness who spoke to ABC 7.

"They approached the vehicle and they started punching in the panels on the vehicle and hitting the windows, breaking the windows. Another vehicle impeded my view so I couldn't see exactly if he was, the man was pulled from the vehicle or if he got out on his own."

"Four to five men were hitting him, kicking him even when he was down, very clearly they broke his leg."

When the bikers left, the videographer says he got out of his vehicle to help Alex. "He had a broken leg as I said. He had a bloodied face. He had road rash. He was in pretty rough shape."

According to a witness in a nearby car who spoke with the Chron, “I saw the male bikers surround the vehicle and started to yell, break side mirrors and also physically hitting the vehicle. It seemed like they were provoking the driver to come out."

The "driver came out of the car when the biker gang started beating him up,” the witness says.

Per the Chron:

Before Alex exited his car, one of the bikers in a red sweatshirt began punching the rear side windows of the Toyota.

The video shows him falling to the ground and tumbling as one of the bikers stood over him and repeatedly punched him. The biker — wearing acid-wash jeans, white sneakers and a dark top — appears to move away from the man as another biker with his helmet on takes over, punching and kicking the driver as he struggles to get up and shield himself.

Alex's sister says that he's undergone surgery for the leg fracture, and is still pretty “out of it."

ABC 7 reports that the California Highway Patrol continues to scrutinize the video in an effort to find the suspects, and asks anyone with knowledge of the attack to call 415-551-4100.

The San Francisco Police Department, which has for years admitted their powerlessness against bike gangs like this one's misbehavior on SF's surface streets, told the Chron that they've recently been especially active in Hayes Valley.

“They’re biking up and down some stairs near some apartment complexes,” SFPD spokesperson Officer Giselle Talkoff said. “We won’t chase them because it’s too dangerous."

According to the witness who caught Wednesday's attack on video, that's not enough. "These guys obviously think they can do just whatever they want," he said.

"These are the types of incidents that really need to get attention and that really need to get prosecuted."

Previously: Driver Who Interrupted Bikers' Sideshow Attacked On San Francisco Freeway