The party turned to chaos after a brawl between Merced Police officers and patrons ended with one officer being assaulted inside Chandelier's Hookah Lounge.
Partygoers said the police officers were the aggressors, but the district attorney's office disagreed after reviewing body camera footage for the past 11 months.
Merced Police had received information that a person sought in connection with an armed robbery had been reported to be in attendance at the party.
Three people have been charged: 23-year-old Isa Bey of Oakland, 21-year-old Nedir Bey of Oakland, and Ciasonne Ratto-Foster of Richmond.