Just after 2 a.m., Petrov crashed into a parked car near Stevenson and 14th streets, according to Deputy Shawn Osborne's report. Petrov jumped from the Mercedes and ran, with deputies Luis Santamaria and Paul Wieber in close foot pursuit.

Wieber and Santamaria wrote in incident reports four days after the arrest that they feared Petrov had a weapon and was leading them into an ambush.

"Because I did not know the street we were on as we pursued Petrov, I was worried that Deputy Wieber and I could be killed or seriously injured," Santamaria wrote in his report.

'They attempt to justify why they beat this man nearly to death, and their explanation doesn't stand up to the video.' Jeff Adachi,

San Francisco public defender

Wieber is about 10 feet behind Petrov when they both enter the frame of a Stevenson Street surveillance camera. Wieber tackles Petrov as he slows and looks over his left shoulder.

The deputy wrote that he slid forward and lost control of Petrov during the tackle and that he felt Petrov attempt to raise himself off the ground.

"Petrov had committed an assault with a deadly weapon against a deputy [when he rammed the deputies' patrol cars in San Leandro] and I had no doubt he would attempt to seriously harm me if given the opportunity," Wieber wrote.

Santamaria began hitting "on his upper left arm to gain his compliance" as Wieber got to his feet, he wrote. Both deputies then continued to strike Petrov more than 30 times as he wriggled on the ground and cried out in pain.

"Petrov refused to surrender and I feared Deputy Santamaria and I were starting to fatigue," Wieber wrote. Both deputies said they felt dizzy from exertion as more deputies started to arrive and began handcuffing Petrov's broken arms.

San Francisco Public Defender Jeff Adachi, who released surveillance video of the arrest on Nov. 13, said the deputies wrote a "legal fiction."

"They obviously wrote this after they were aware of the video that we released," Adachi said. "They attempt to justify why they beat this man nearly to death, and their explanation doesn't stand up to the video."

Alameda County Sheriff's Office spokesman Sgt. Ray Kelly said it wasn't uncommon for the deputies to have filed reports four days after the arrest, and especially so during the investigation of the Petrov beating. He said the deputies requested attorneys before writing their reports.

"It was likely that this case could be punitive," he said. "They requested attorneys, and so the department has to afford them. We have to comply when they want an attorney."

Kelly said no law or policy would have prevented Wieber and Santamaria from viewing the video between its release on a Friday and submitting their reports the following Monday.

"I think the video had gone pretty viral at that point," he said. "So it's probably obvious."

Civil rights attorney Michael Haddad is representing Petrov. He said Wieber and Santamaria wrote "CYA reports."

"Basically they knew the jig was up, and so you can see them writing very defensively trying to justify the multiple deadly force head strikes with steel batons," he said.

Wieber and Santamaria remain on paid administrative leave pending the outcome of an internal investigation into the arrest, Kelly said. He said their incident reports, as well as those of 20 other sheriff's deputies involved in the incident and investigation, should not have been released.

"I don't think it's going to affect the case and the investigation at this point," he said, adding that the reports would have been released at some point. "It came to light sooner rather than later."

Deputy Sierry Wilhelm wrote in a follow-up report Nov. 16 that none of the 11 deputies or two sergeants involved in the incident had activated their body-worn cameras. Activation of the cameras is optional under the sheriff's current policy, which is going to change. Kelly said Petrov's arrest had a lot to do with that.

"We're aware that 11 cameras were not activated," he said. "That's concerning and that's one of the reasons that we're looking at new technologies with auto-activation. ... They consciously would have to turn it off. We're looking at fail-proof systems for activation, so the officers don't forget or whatever."

Adachi and Haddad both said the failure of so many deputies to activate body cameras concerns them.

"You don't turn your camera on if you're committing a crime," Haddad said, "and that's probably what's happening here."

Haddad said he's held off on filing a civil claim to give the San Francisco district attorney time to file criminal charges against Wieber, Santamaria and any other deputies or officers involved in the incident, but time is running out.

"It didn't take more than a few days to look at the video and determine that these officers committed crimes and clearly acted outside of any legitimate law enforcement policy," he said.