Two Northern California sheriff's deputies seen beating a suspect on surveillance video last year have been slapped with a civil lawsuit, along with a third deputy accused of bribing homeless witnesses with the man's belongings in exchange for their silence.

The man's lawyer, Michael Haddad, said an Alameda County sheriff's deputy approached a homeless couple in a Mission District alley after the November beating of Stanislav Petrov and gave them Petrov's large gold chain with a medallion, cash and cigarettes so they would not speak out about what they saw. One deputy also is accused of taking a so-called trophy picture with Petrov after he was beaten.

"I think it was implied that he wanted them to be quiet,'' Haddad said of the exchange, adding that he had spoken with the homeless onlookers.

Haddad, who said the beating meted out to 29-year-old Petrov is indefensible, on Tuesday filed a claim against the Alameda County Sheriff's Department, alleging the deputies' use of force was excessive and unjustified.

"This is probably the worst law enforcement beating on video we've seen since Rodney King," he said. "[Stanislav Petrov] would like justice. This is outrageous and he wishes it had never happened."

King was a taxi driver who was beaten by Los Angeles Police Department officers following a high-speed car chase in 1991.

Sgt. J.D. Nelson, a spokesman for the sheriff's office, told reporters the agency is investigating the incident.

"They are no better than the criminals they arrested, if these allegations are true,'' Nelson said about the deputies. "We get a little ticked off when things like this happen because it tarnishes my badge and it tarnishes everybody's badge and we don't like it."

Two Alameda County sheriff’s deputies, who were seen beating a suspect on surveillance video last year, and a third deputy, accused of bribing homeless witnesses with the man’s belongings, have been slapped with a civil lawsuit. Bob Redell reports.

The deputies have been on paid administrative leave since the San Francisco public defender's office released video showing the deputies repeatedly hitting a man with their batons as he screamed. He had broken bones in both hands and severe bruising to the head and body, his attorney said.

"If that allegation is true it's one of the most horrific things I've ever heard," at a news conference Tuesday, Alameda County Sheriff Gregory Ahern said.

Ahern also promised a thorough investigation, saying that the department is taking steps to ensure such an incident never reoccurs. He says every deputy on the scene will have to justify his conduct.

"They’re responsible for every word and every action that took place at the scene," he stressed. "If I find they violated policy, they will be disciplined."

The incident began when authorities spotted Petrov in a stolen car in Castro Valley. Petrov rammed two deputies' vehicles and then led law enforcement on a chase across the Oakland-San Francisco Bay Bridge before deputies on foot caught up to him in the Mission District of San Francisco, according to the sheriff's office.

Petrov was resisting arrest and reaching for his waistband, which made the deputies fear he was armed, according to their statements.

San Francisco District Attorney George Gascon says he has not decided whether he will charge the deputies.

In an email to NBC Bay Area, Assistant District Attorney Alex Bastian said, "As with every case that comes into this office, we must be sure that a thorough investigation has been conducted so that justice is done." He also declined to comment further on the incident.

Haddad, however, questioned the deputies' statements, which were taken four days after the video was released.

"I'm suspicious that these are false reports that probably replaced earlier reports that were thrown away,'' Haddad said.

After months of saying that the deputies' body-worn cameras were not switched on during the incident, the sheriff's office said Monday that one of the deputies may have accidentally captured the beating.

Alameda County Sheriff's deputies must now activate their body-worn cameras while on duty or face termination, Ahern added.