The man charged with murdering a Martinez resident one day after his release on Orinda burglary charges had a history in Lamorinda that included a domestic violence report in Lafayette and a diversion program that let him avoid prosecution, according to East Bay Times reporting published Aug. 12.

Marcos Iriarte-Valdez, 36, was formally charged Tuesday, Aug. 11, with the murder of Todd Stewart, 68, who was fatally stabbed Thursday, Aug. 6, during what prosecutors say was a daytime residential burglary on Francis Court in Martinez. As we reported Thursday, Aug. 13, Iriarte-Valdez had been released the previous day on pending felony charges for two April 29 burglaries in Orinda's Orinda Downs neighborhood.

His contact with law enforcement began more than a year earlier, in Lafayette.

The Lafayette report

On Jan. 9, 2025, Iriarte-Valdez's ex-girlfriend reported him to police at their once-shared Lafayette apartment, according to court records cited by the East Bay Times. She told officers he slammed her laptop shut and grabbed her by the throat, choking and scratching her. The attack stopped when she grabbed a stun gun and threatened him with it.

During the police interview, the woman also told investigators she had found videos on Iriarte-Valdez's laptop of teen girls being sexually abused, including categories labeled "16 and up" and "17+," according to court records. The warrant went nowhere. Authorities were unable to locate the device.

The woman obtained a restraining order. In April 2025, Iriarte-Valdez was charged with a misdemeanor for violating that order. Contra Costa Superior Court Judge Jesse Hsieh allowed him to resolve the case through a diversion program scheduled to run through February 2027, according to court records.

Orinda burglaries and the Kowalczyk decision

By April 29, 2026, Iriarte-Valdez was charged with two counts of felony first-degree burglary after entering homes on a cul-de-sac off Dalewood Drive in Orinda Downs while residents were inside. An 83-year-old woman reported a man stole a laptop from her garage and took food from her refrigerator. A neighbor spotted the same man trying to enter her back door and screamed, causing him to flee.

Two separate Contra Costa judges then released Iriarte-Valdez over a three-month span, a sequence the East Bay Times reported was likely driven by the California Supreme Court's April 30 Kowalczyk decision. That unanimous ruling, authored by Chief Justice Patricia Guerrero, requires bail to be set at amounts "reasonably attainable" for defendants charged with non-violent, non-sex felonies unless prosecutors can show clear and convincing evidence the person is likely to seriously hurt someone or skip court, according to CalMatters.

Judge Hsieh initially released Iriarte-Valdez in May and placed him on electronic home detention. After he was accused of violating those terms, Judge Nichelle Holmes, a former Contra Costa prosecutor, released him on his own recognizance Wednesday, Aug. 5, according to court records cited by the East Bay Times.

The monitoring gap

Iriarte-Valdez was not fitted with an electronic ankle monitor after his Wednesday, Aug. 5, release until the morning of Saturday, Aug. 8, two days after the killing, Martinez Police Chief Andrew White confirmed to Martinez News and Views. The bracelet had been removed when he was taken into custody Tuesday, Aug. 4, and was never replaced upon release.

Stewart was working in his open garage when the confrontation occurred, according to White, who told NBC Bay Area the attack had "no known connection to the victim."

Arraignment and what's next

At his Wednesday, Aug. 12, arraignment, Iriarte-Valdez pleaded not guilty to murder and three special enhancements: killing during a burglary, personal use of a knife and committing the offense while on conditional release. Judge David Goldstein called him "a risk to public safety" and ordered him held without bail, according to the Contra Costa County District Attorney's Office.

If a jury finds the burglary-murder enhancement true, Iriarte-Valdez would be eligible for life without parole.

The murder case returns to court Tuesday, Sept. 1, at 8:30 a.m. before Judge Michael Nieto in Richmond to set a preliminary hearing date. The Orinda Downs burglary cases remain pending with no next court date announced.