Suspect Identified in Thirty-Year Cold Case Homicide of Alameda Resident

Suspect Identified in Thirty-Year Cold Case Homicide of Alameda Resident

A 30-year cold case murder of an Alameda woman was closed by the San Mateo County Sheriff’s Office (SMSO) on August 2 after the suspect’s whereabouts were discovered.

According to an SMSO press release, fingerprint analysis confirmed the identity and location of Gregory Marc Rivera, the lone suspect in the murder of Alameda resident Juliette Rivera, 25, who was killed in 1992. Juliette and Gregory were acquaintances and not related.

On July 7, 1992, Juliette was reported missing in Alameda. Alameda Police Department (APD) investigators questioned Gregory, who was also an Alameda resident at the time. APD investigators believed Gregory was a suspect after he provided them with inconsistent information during questioning, according to the press release.

On July 17, 1992, a farm worker in an unincorporated area of the San Mateo County South Coast area found a decomposing body of a woman near an irrigation pond. The body was identified as Juliette and an autopsy showed she died of blunt force trauma. The SMSO issued an arrest warrant for Gregory on August 7, 1992. However, Gregory had already left his Alameda residence. Gregory eluded law enforcement for the next 30 years.

On May 12, Merced County Coroner’s Office (MCCO) notified they were in possession of the deceased body of Gregory. According to the MCCO, Gregory died on January 29. When MCCO discovered his deceased body all they knew was that the man was a transient. To locate his next of kin, they conducted fingerprint analysis. The MCCO learned the body was Gregory and that he had an active arrest warrant for Juliette’s murder out of San Mateo.

After contacting SMSO, the two agencies worked to confirm the body was Gregory. They learned that Gregory used aliases: Abraham Rivera and John Paul Rivera, the name of his brother. SMSO spoke with John Paul’s daughter who told them her father was still alive. She also told them the brothers would use each other’s identity to elude law enforcement.

"The closure of this 30-year-old cold case homicide could not have been possible with the assistance of the Alameda Police Department, Merced County Sheriff’s Office and Coroner Bureau, and the San Mateo County District Attorney’s Office,” stated the SMSO press release.