The case began with a burning SUV rolling down a quiet street in Orange, not far from Chapman University. Inside, authorities discovered three charred bodies, all with gunshot wounds.
Six days later, a decomposing body turned up in Fontana with a gunshot wound to the back the head. The San Bernardino County coroner's office would identify that body as the brother of one those in the burned SUV.
On Tuesday, Orange County prosecutors formally charged Alejandro Guerrero Ruiz, 23, with the killings. He faces four counts of murder with the special circumstances of multiple murder and murder during the commission of a robbery.
Investigators said they believe that the deaths were associated with a narcotics trafficking heist.
The robbery targeted "either or both" narcotics and money, said Scott Simmons, an Orange County deputy district attorney.
Authorities are also looking for other possible suspects, Simmons said. A surveillance video of the rolling SUV showed someone other than Ruiz jumping from the vehicle before it crashed to a halt, officials said.
Orange police detectives say the killings all occurred Nov. 9, 2015.
The bodies inside the vehicle -- which was found in the 500 block of East Oakmont Avenue -- were identified as 19-year-old Antonio Medina of Glendale, Ariz.; 26-year-old Edgar Berrelleza-Soto of Orange and Fernando Meza, 20, of Phoenix.
The fourth victim, prosecutors say, was 35-year-old Joel Mauricio Berrelleza, the brother of Berrelleza-Soto. His body was discovered Nov. 15.
Ruiz, a resident of Mexico, remains in the custody of federal authorities in Texas awaiting extradition to California. Prosecutors said he was initially detained on an immigration hold.