The Hells Angels biker gang is suspected of the brutal beating of a man after a Lauryn Hill concert

The Hells Angels biker gang is suspected of the brutal beating of a man after a Lauryn Hill concert Tuesday night at the Warfield Theatre, San Francisco police said Wednesday.

The victim and the group of about 10 bikers had been attending the Lauryn Hill concert at The Warfield when they got into an altercation in the lobby of the music venue, San Francisco Police Department  Sgt. Michael Andraychak said.

Two men, ages 35 and 39, were leaving the concert venue when they were approached by a group of about 10 men who were wearing Hells Angels jackets and had apparently also been at the concert, police Sgt. Mike Andraychak said.

One of the suspects asked the 35-year-old victim if he was a member of the Mongols, a rival motorcycle gang, police said.

“They heard somebody yelling from behind, ‘Aren’t you from the Mongols?’” Andraychak said.

The Hells Angels and Mongols are rival motorcycle clubs. Andraychak said neither victim is believed to be associated with any motorcycle gang.

The victims ran away and were chased by the suspects, who caught up with them and stabbed the 35-year-old man several times, police said.

Andraychak said the beating that followed “appears to be a case of mistaken identity.”

After one biker punched the man with a closed fist, several others joined in on the beating, Andraychak said. The victim’s injuries were serious but not life threatening, police said.

The suspects fled the scene on their motorcycles and had not been found as of Wednesday afternoon, Andraychak said.

They are described as white men in their 30s or 40s, at least one of whom had a full Hells Angels logo on his jacket, Andraychak said. Others had partial patches, signifying that they are "prospects or pledges" to the gang but are not yet full members, he said.

The two motorcycle gangs have a history of run-ins in San Francisco and throughout California, Andraychak said.

In 2008, Mark "Papa" Guardado, 46, was fatally shot outside a bar in The City's Mission District.

Guardado was the leader of the San Francisco chapter of the Hells Angels and his alleged shooter, Christopher Ablett, was a reputed member of the Mongols.

Federal murder and racketeering charges were filed against Ablett. The case is still pending in federal court.