The suspects, Joshua Garrard, 18, Timothy Hall, 20, Shamron Mitchell, 19, and a 16-year-old boy were arrested at their homes Thursday for false imprisonment, assault with a deadly weapon, conspiracy to commit a crime and participating in a criminal street gang, the sheriff's office said.
Hall and the juvenile are being held under no-bail probation holds and Garrard and Mitchell are being held under $200,000 bail.
The four assault victims between ages 18 and 31 were attending a Labor Day festival around 6 p.m. Sept. 1 in the 100 block of Drake Avenue when the suspects challenged them to fight, the sheriff's office said.
Authorities believe the victims were targeted because they were not from Marin City. The victims decided to leave but were followed by the suspects, the sheriff's office said.
The suspects surrounded the victims and punched, kicked and beat them with sticks and metal poles, the sheriff's office said. The victims retreated to a nearby residence on Cole Drive but the suspects threw a bicycle and rocks through the window of the apartment where the victims were hiding, authorities said.
A follow-up investigation led to the identities of the four suspects, the sheriff's office said.