On July 17, 1988, Julie McGhee, 29 and a prostitute, disappeared after being picked up by an unknown male in the Cathedral City area of Riverside County. Her remains, stripped of identification, were later found in a remote desert area. Identifying her body was made more difficult by the mutilation of her body by coyotes and possibly other animals. Cartridge cases for a .45-caliber handgun were found near McGhee's body. McGhee's slaying was initially investigated as a single, isolated homicide.
Two months later, on September 25, 1988, another prostitute, Mary Ann Wells, 31, was picked up by someone in nearby San Diego County and driven to a deserted industrial complex within the City of San Diego. Her body was found later, shot once in the head. As in McGhee's death, a cartridge case was left behind at the scene of Wells' murder. A condom found at the scene had the Wells' DNA on it, as well as DNA from another person—believed to be the killer's—but the stranger's DNA did not immediately lead anywhere.
By the time of the next slaying some seven months later, again in Riverside County, investigators began to see the links between the deaths. On April 16, 1989, another prostitute, Tammie Erwin, 20, was picked up and driven to a remote area near Palm Springs where she was shot three times and her body dumped. Again investigators found cartridge cases near the body.
Investigators from Riverside and San Diego counties began comparing notes. They realized that they had a serial killer on their hands: ballistics tests showed that the cartridge cases from the McGhee, Wells, and Erwin murders scenes all matched. Each of the women had been killed with the same gun, but they lacked, at this point, both the weapon and a suspect to whom they could link it.
But there was no link between the prostitute shootings and the murder of Robbin Brandley. The victim contrasts were too great: Brandley wasn't a prostitute; she was a college student. Brandley also had not been shot; she had been repeatedly stabbed. For the next three and a half years there were no additional murders that police could attribute to the same killer.