The San Francisco Public Defender's Office released a video on Friday evening via Twitter that shows Alameda County sheriff's deputies repeatedly striking a man on the ground with their batons.

Here's the original tweet for the full context. The video, which clocks in at 13 minutes, has ten second-long lapses, which means that the beating actually lasted longer than depicted here.

It's not pretty. Tamara Aparton, spokesperson for the Public Defender's office told the SF Examiner, "It's extremely disturbing...[The victim] doesn't appear to be resisting at all. We want to find out the circumstances of his arrest, and the extent of his injures as soon as we can." In addition to the graphic violence of the beating itself, the rest of the video is disturbing as well, when we see the victim on the ground, surrounded by several other officers. "He's begging for help," Aparton said. She also added that on Friday, the day after the incident, a puddle of blood was seen on the street where the beating took place.

The Examiner reports that the incident occurred around 3 a.m. on Clinton Park, near the intersection with Valencia Street. The Public Defender's office says that the two men beating the victim are Alameda County Sheriff's Deputies.

According to CBS SF, the pursuit began after deputies who had been patrolling a hotel parking lot in San Leandro saw a stolen 2015 Mercedes. Alameda County sheriff’s Sgt. Ray Kelly said that when the deputies approached the car, the suspect started the car and ignored their orders to stop. The driver then allegedly crashed into two police cars and injured one deputy, before leading the deputies on a chase that took them on Interstate Highway 580 into Oakland, before heading west into San Francisco. Kelly said that the driver crossed the Bay Bridge at speeds of more than 100 miles per hour.

Once the driver exited the freeway in San Francisco, he struck a parked car and then fled on foot before deputies caught up to him. This is when the video starts.

Kelly said that the department had been alerted to the video after it had been posted on Friday afternoon, and that an internal affairs investigation is already underway. "We're going to do a complete and thorough investigation into this incident and figure it out," he said.

The suspect, Stanislav Petrov, was taken to San Francisco General Hospital to be treated for his injuries sustained during the beaten.