(KRON) — Nearly 44 years after the stabbing death of an 18-year-old security guard in Sunnyvale, the cold case murder suspect has been identified, the Sunnyvale Department of Public Safety announced Thursday.

In 1979, Estella Elena Mena worked as a security guard in Sunnyvale for a business located at 444 De Guigne Drive, officials said. On Oct. 27 of that year, Sunnyvale DPS officers responded to a report of an assault at the business and located Mena in the lobby suffering from multiple stab wounds.

Sunnyvale DPS said that there were no leads on suspects for years following the killing.

Estella Elena Mena (Photo: Sunnyvale DPS)

A DNA profile from blood evidence collected at the crime scene was run through CODIS, a national DNA database, at that time. There were no matches on the profile.

Decades later, in Oct. 2022, officials said the DNA profile was submitted for Forensic Investigative Genealogy. A new lead was developed, and the source of the blood at the scene was positively identified. However, investigators were able to eliminate that individual from suspicion in the homicide.

A second DNA profile was then created from items directly connected to Mena, police said. CODIS was again used on this profile, and Samuel Silva, born March 29, 1961, was positively identified as a match.

Investigators learned Silva was a former resident of Sunnyvale with a “lengthy criminal history which included sexual assault and violent crime,” Sunnyvale DPS said. Silva would later live in Colorado, where he died in 2008.

After further investigations, including gathering more evidence of Silva’s involvement and conducting interviews, Sunnyvale DPS announced on Oct. 26, 2023, that the cold case was now closed by naming Silva as the perpetrator.

Samuel Silva (Photo: Sunnyvale DPS)

The announcement comes one day before the 44th anniversary of Mena’s death.

In a statement, Sunnyvale DPS acknowledged her family and thanked multiple agencies that worked together in the investigation, including the Santa Clara County District Attorney’s Office Cold Case Unit, Santa Clara County Crime Laboratory and multiple Colorado law enforcement agencies.