Arrest Made In Martinez Murder Friday; Suspect On Pre-Trial Release For Orinda Burglaries

Heavily armed special weapons officers descended on an Ashwood Drive condo this evening and arrested a suspect in Thursday’s brutal murder of a 68-year-old Martinez man on Francis Court.

The silver Cadillac SUV spotted outside the murder scene was also located and towed away for processing..

Todd Stewart, 68, was confronted by a man wearing a tactical weapons vest and gloves as he worked in his garage, the suspect attacking Stewart and stabbing him repeatedly as Stewart called for help. After the attack, the suspect drove away in a silver colored Cadillac SUV – which was reportedly recovered during tonight’s arrest.

The scene of the attack is a mere 8 minute drive from where the suspect was taken into custody tonight. Chief Andrew White released the following subsequent to Friday’s arrest:

Following the initial report of the stabbing homicide on Francis Court, the Martinez Police Department worked to identify and locate the suspect. With the help of the community and other agencies, a license plate was identified and the vehicle was located in the 1600 block of Ashwood Drive in Martinez. Officers began surveillance of the suspect and vehicle while detectives conducted additional investigation.

The suspect was identified as Marcos Iriarte-Valdez, 36, who lives in the 1600 block of Ashwood Drive. A review of court records showed:

• Valdez was on pre-trial release for residential burglaries (with persons present) that occurred on April 29, 2026 in Orinda.
• On August 4, 2026, Valdez was taken into custody for allegedly violating a home detention monitoring rule.
• On August 5, 2026, Valdez was ordered released on his own-recognizance and referred to home detention monitoring.

Based on information gathered, detectives obtained an arrest warrant from the Contra Costa County Superior Court for Valdez for murder and committing a felony while on own-recognizance release. They also obtained a search warrant for Valdez’s home and vehicle.

On August 7, 2026, around 6:23pm, the warrants were executed by the Central County SWAT team and the suspect was taken into custody. The suspect is being booked into jail with a bail set at $1.1 million.

The investigation is ongoing and our understanding of the incident may change as more individuals are interviewed and evidence is collected and analyzed.