"It is increasingly clear that gang violence is at the center of this tragedy," the Sacramento Police Department said in an update on the mass shooting. "While we cannot at this time elaborate on the precise gang affiliation of individuals involved, gangs and gang violence are inseparable from the events that drove these shootings."
Two brothers – 26-year-old Dandrae Martin and 27-year-old Smiley Martin – were arrested earlier in the week in connection with the shooting.
Smiley Martin was seriously injured by gunfire in the shooting and brandished a firearm on Facebook Live just hours before the gunfight, investigators told the Associated Press.
He has a criminal history that dates back to 2013 and was released from prison in February after serving time for punching his girlfriend and whipping her with a belt. A parole board had previously rejected his bid for an early release as prosecutors said he posed "a significant, unreasonable risk of safety to the community."
Smiley is facing charges of possession of a firearm by a prohibited person and possession of a machine gun, while Dandrae was charged with assault with a deadly weapon and unlawful possession of a firearm by a felon. District Attorney Anne Marie Schubert said more charges could be filed.
A third suspect, 31-year-old Daviyonne Dawson, was arrested Monday night on suspicion of being a prohibited person in possession of a firearm. Sacramento police said he was seen carrying a gun right after the shooting but is not charged with crimes directly related to the shooting.
The shooting started following a possible fight as bars closed down around 2:00 a.m. and people flooded out into the streets.
More than 100 shell casings were recovered from the scene and multiple buildings and vehicles were struck by gunfire.
Members of the public have provided a "a remarkable level of assistance" in the investigation, sending in nearly 200 videos, photographs, and other pieces of evidence, police said Wednesday in an appeal for more help.
"This tragedy downtown is a very public example of what families in many of our neighborhoods know too well," Sacramento Police Chief Kathy Lester said Wednesday. "The suffering inflicted by gang violence does not limit itself to gang members. It spills over to claim and shatter innocent lives and harm our entire community."
The six deceased victims are Johntaya Alexander, 21; Melinda Davis, 57; Yamile Martinez-Andrade, 21; Sergio Harris, 38; Joshua Hoye-Lucchesi, 32; and De’vazia Turner, 29.
The Associated Press contributed to this report.