Alfonso Mendoza Ramirez, 18, was arrested around 9:30 p.m. after police served a search warrant at his home in the 3000 block of Louis Krohn Drive in Santa Rosa, Sgt. Steve Fraga said.
Ramirez has been identified as a principal participant in the murder of Christopher Medina Ochoa, 23, of Santa Rosa, according to police.
He was booked into Sonoma County Jail on suspicion of murder and attempted murder, and is being held without bail, according to police. He will be arraigned Friday afternoon in Sonoma County Superior Court.
Santa Rosa police found Ochoa and a second victim, Jullian Loeza Jr., 21, of Santa Rosa, lying in the parking lot outside the El Puente Cantina at 1709 Santa Rosa Ave. around 1:55 a.m. Saturday.
Both victims were taken to a hospital, where Ochoa was pronounced dead and Loeza Jr. was admitted for surgery, police said.
On Tuesday, two other suspects who have been charged in the restaurant shooting delayed entering pleas. Their next court date is Dec. 15.
The first suspect, Jose Campos-Mendoza, 17, of Santa Rosa, is being tried as an adult for Ochoa's murder. He also faces two counts of attempted murder and assault with a deadly weapon.
The attempted murder charges stem from shooting Loeza Jr. and shooting at a security guard who was nearly hit by the gunfire, Sonoma County Deputy District Attorney Craig Brooks said.
The second suspect, Daniel Calderon-Escobido, 23, of Petaluma, is charged with being an accessory to those charges.
Witnesses to the shootings gave descriptions of the suspects, and Calderon-Escobido was arrested at the scene Saturday, Fraga said.
Campos-Mendoza was arrested nearby on U.S. Highway 101 Saturday, Fraga said. Police recovered a weapon at the scene.
"There was an argument or some sort of conflict among friends and family at the restaurant," Fraga said this morning.
He alleged that Ramirez "acted in concert" with Campos-Mendoza, the alleged shooter. The shootings remain under investigation but there are no other known suspects.
