DNA confirms – Sonoma County investigators say DNA linked Oscar Bolanos to the 1983 sexual assault and stabbing death of Robert Pangborn, a case that stayed unsolved for more than 40 years despite preserved evidence. Bolanos, 67, died in April 2026 in El Salvador before any
For more than four decades. investigators kept looking for the answer to a murder that began in Guerneville. California—about 20 miles northwest of Santa Rosa—and ended with Robert Pangborn found partially clothed and fatally stabbed. Now, the Sonoma County Sheriff’s Office says DNA has finally put a name to the killer.
In a statement released by the sheriff’s office, detectives identified Oscar Bolanos, 67, as the man responsible for the May 21, 1983 assault and killing of Pangborn. The office said Bolanos died in April 2026, meaning he will not face a courtroom prosecution in the United States.
The case had sat in the backlog of cold investigations that Sonoma County detectives frequently review. At the time of the killing, investigators collected and preserved physical evidence but were unable to narrow down a suspect. The sheriff’s office said the reason was simple and brutally limiting: “DNA technology was not yet available to law enforcement.”.
Between 2010 and 2023. evidence tied to Pangborn’s case was submitted for advanced DNA testing. first to the Santa Clara County Crime Laboratory and later to the Serological Research Institute in Richmond. California. Investigators said that as time passed, new methods became available—and those methods ultimately connected Bolanos to Pangborn.
In 2024, 41 years after Pangborn’s death, DNA linked Bolanos to the case, the sheriff’s office said. The office did not say whether Pangborn and Bolanos knew each other. On May 29. the sheriff’s office also could not answer questions about whether Pangborn was found dead in his home or somewhere else. nor could it say who found him after the assault and stabbing.
Bolanos served time in another case that dated to the early 1990s. The sheriff’s office said he first came to the United States on a work visa in the early 1980s. In 1992. nearly a decade after Pangborn’s assault. Bolanos was arrested in Los Angeles County in connection with the sodomization and sexual assault of a juvenile. The assault happened in September 1992 and his victim was under 14 years old, according to online court records.
DNA from the 1992 case was entered into law enforcement databases, the sheriff’s office said. Bolanos served time in state prison for his offenses, the office added.
How to find him after the trail went cold was the next problem. When Sonoma County detectives began looking into Pangborn’s 1983 cold case. they learned Bolanos had been released from prison in 1994 and deported to El Salvador. Detectives then contacted the Department of Justice and Homeland Security. as well as the Federal Bureau of Investigation. to determine Bolanos’ location.
The sheriff’s office said authorities learned he never returned to the United States after he was deported. It also said authorities in El Salvador told detectives Bolanos was living near the same village he previously listed on his visa application.
Once detectives had that information, the case moved into federal and international logistics. The sheriff’s office said it presented the matter to the Sonoma County District Attorney’s Office so prosecutors could seek an arrest warrant for murder. Sonoma County detectives worked with federal authorities and the Salvadoran government to have Bolanos arrested and extradited to the United States to stand trial in Pangborn’s case.
In April 2026, federal authorities were trying to take him into custody when they learned he had been found dead in his home in El Salvador. The sheriff’s office wrote that investigators learned Bolanos had reportedly been battling cancer and appeared to have died of natural causes.
“Although Bolanos will not face prosecution in court, the Sonoma County Sheriff’s Office has concluded that the evidence establishes he sexually assaulted and murdered Robert Pangborn,” the office said.
The sequence of events—preserved evidence. decades of technological change. and then a late DNA link to a suspect who had already left the country—changed what justice could look like in this case. Investigators say they now have the confirmation they couldn’t reach in 1983. They just arrived at it after Bolanos was already gone.
Sonoma County Sheriff’s Office Robert Pangborn Oscar Bolanos cold case DNA testing Serological Research Institute Santa Clara County Crime Laboratory Guerneville El Salvador deportation murder arrest warrant extradition