Martinez, California – On August 6, 2026, Todd Stewart, 68, was fatally stabbed outside a residence on Francis Court around 5:09 p.m. Multiple 911 calls reported the incident.
Martinez Police Department officers responded and found Stewart with injuries consistent with stabbing. He was pronounced dead at the scene. Stewart was working in his open garage. The suspect fled in a Cadillac SUV.
On August 7, 2026, around 6:23 p.m., Marcos Iriarte-Valdez, 36, was arrested at his home in the 1600 block of Ashwood Drive in Martinez by the Central County SWAT team.
Detectives obtained warrants for murder and for committing a felony while on own-recognizance (OR) release, plus a search of his home and vehicle. He was booked with bail set at $1.1 million. The Contra Costa County District Attorney’s Office charged him with special-circumstance murder while fleeing a burglary attempt. He is held without bail pending arraignment.
According to the Department of Homeland Security, Iriarte-Valdez is a criminal illegal alien from Venezuela who also holds citizenship in Spain. On August 8, 2026, ICE placed a detainer on him with the Contra Costa County Jail.
Surveillance video, license plate recognition, and community tips identified the suspect. Police Chief Andrew White stated that no known connection existed between Iriarte-Valdez and Stewart, and no motive had been established.
Iriarte-Valdez was released from jail on August 5, 2026 (the day before, on his own recognizance and referred to home-detention monitoring after custody on August 4 for an alleged monitoring violation.
Court records show pretrial release for two counts of felony first-degree residential burglary (with persons present) from April 29, 2026, in Orinda, to which he pleaded not guilty. He was in diversion for a 2025 misdemeanor protective-order violation. In October 2025, Martinez police arrested him on suspicion of hit-and-run property damage; the District Attorney declined charges for insufficient evidence. Prior arrests include 2016 suspicion of forcible rape and corporal injury on a spouse/cohabitant, and 2015 public intoxication in San Luis Obispo.
