Transient Man ID’d As Murder Suspect Posed As Brother To Avoid Arrest In 1992 Murder

A California man who evaded capture for decades after being identified as a suspect in the murder of 25-year-old woman more than 30 years ago was found dead after living under his brother’s name.

Gregory Marc Riviera, who had been wanted in the 1992 murder of Juliette Rivera, avoided detection for decades by assuming his sibling’s identity and a transient lifestyle, according to a San Mateo County Sheriff’s Office press release sent to Oxygen.com. 

Riviera, who had been living under the fictitious name “John Paul,” died in May. He was positively identified through fingerprint analysis. Police now suspect the man frequently swapped names with his brother to avoid arrest in the decades-old slaying.

“Here at the San Mateo County Sheriff’s Office, a cold case does not mean a closed case,” public information officer Lt. Eamonn Allen told Law&Crime. “We investigate all cases thoroughly.” 

Juliette Rivera was reported missing on July 7, 1992. A week later, a farmer discovered her corpse near an irrigation pond in a rural area of unincorporated San Mateo County. She died from blunt force trauma from a flat object to the back and left side of her skull, according to an autopsy.

Riviera, an acquaintance of the slain woman, was previously identified as a suspect in the case after he provided conflicting statements to police prior to her body being found. 

By the time authorities had secured an arrest warrant, however, Riviera’s apartment in Alameda had been abandoned. For years — up until his recent death — law enforcement were unable to trace Riviera’s whereabouts. The California man, who also went by Abraham Riviera, was 50 when he vanished.

In May, cold case investigators received a break after the coroner’s office in Merced County identified a transient man who had recently died as Riviera.

Investigators later discovered Riviera had a living brother named John Paul, the same name he'd been living under. Authorities, who interviewed the elderly man’s daughter, ultimately learned the two brothers had often exchanged identities over the years in order to deter any police scrutiny.

“She confirmed John Paul was still alive, but suffering with medical issues,” the San Mateo Sheriff’s Office said in a statement. “She added Gregory and his brother had used each other’s identity for the past 30 years to elude law enforcement.”

Authorities are now banking on additional public tips to shed further light on Riviera’s involvement in Juliette Rivera’s killing.

“Based on this investigation with the identity of suspect Abraham Rivera AKA Gregory Marc Riviera AKA Jon Paul, finally located and now deceased, this case is closed,” the sheriff’s statement added.

A spokesperson for the San Mateo County Sheriff’s Office wasn’t immediately available for comment when contacted by Oxygen.com on Wednesday. 

Anyone with additional information pertaining to the Juliette Rivera’s killing is urged to contact the San Mateo County Sheriff’s Office’s Cold Case Unit at coldcase@smcgov.org.