SAPD Officer Mark Castillo Charged With Aggravated Assault in La Cantera Shooting — Case Tracker

CASE FILE — THE CASTILLO CASE. Charged with: aggravated assault with a deadly weapon. Arrested: Oct. 16, 2026, on a warrant arising from an off-duty incident on Sept. 26, 2026, at the Shops at La Cantera. Department status: placed on administrative duty with the Patrol Division. Investigations open: SAPD says a criminal investigation and an administrative investigation are both under way. Next step: magistration and the first Bexar County court settings. Castillo is charged, not convicted, and is presumed innocent unless proven guilty.

The San Antonio Police Department announced on Oct. 16 that Officer Mark Castillo had been arrested for aggravated assault with a deadly weapon following the issuance of an arrest warrant for the off-duty incident. In its news release, the department said Castillo is a 25-year veteran currently assigned to the Patrol Division, that he has been placed on administrative duty, and that “The San Antonio Police Department is conducting both a criminal and administrative investigation into this incident.”

The allegations come from an arrest affidavit obtained by KSAT. In the affidavit's account of Sept. 26, Castillo and a DoorDash driver got into a dispute over parking at the Northwest Side shopping center. The affidavit states that Castillo lifted his shirt to show a gun on his waistband, then pulled the weapon and asked, “What do you want to do?” Witnesses intervened and broke up the confrontation, and the driver went on to complete his delivery.

What happened next is the core of the criminal case. The driver told police that after the delivery, Castillo approached him again and the confrontation resumed. According to the affidavit, Castillo fired, shattering the rear window of the driver's vehicle as the driver tried to leave. Investigators used mall surveillance footage to identify Castillo after he left the scene, and a witness also captured the shooting on video, according to the affidavit reporting. No account published so far reports that the driver was struck.

Castillo's account differs on the central fact. Interviewed by SAPD Internal Affairs, he acknowledged that he displayed his handgun when he argued with the driver but denied firing it, maintaining that he had punched out the vehicle's back window, according to KSAT's reporting. Whether that window was broken by a bullet or by a fist is the question the criminal case will have to answer.

Bexar County court records list the defendant as Mark Anthony Castillo, 55, with an arrest date of Oct. 16; at last report he was pending magistration. Texas Commission on Law Enforcement records show his SAPD employment began June 25, 2001 — a quarter-century on the force. By 2024, he was serving on Chief William McManus's executive protection detail, the unit that transported the chief to meetings and events and provided security at scenes.

The arrest is not Castillo's first appearance in the public record, and this desk reports that history as context, not as evidence in the new charge. In July 2024, KSAT reported that Castillo had exchanged sexually explicit text messages with a woman while on duty on the chief's detail, comparing the messages against city work records. City disciplinary records later showed a 30-day suspension, served Oct. 1–30, 2024; a proposed 45-day suspension had been reduced after Castillo met with McManus, according to KSAT. He was removed from the executive detail and moved to the department's vehicle crimes unit.

In May 2025, Castillo was the officer who shot and critically injured a man outside a North Side restaurant. KSAT reported that Castillo, responding to a reported theft at the Thai Hut on North Loop 1604 West, shot Sheldon Malachi Butts, 24, after police said Butts attacked him and tried to reach for his holster during a struggle. Butts was charged with assaulting a peace officer and attempting to take an officer's weapon; Castillo was not charged in that incident. It is part of the record around this officer — it is not proof of anything in the La Cantera case.

Where the case stands: the criminal charge is at its earliest stage in Bexar County, with magistration pending at last report and no trial setting yet. Two department processes run alongside it — the criminal investigation SAPD described in its release and the administrative investigation that will decide Castillo's future with the department — while he remains on administrative duty. This tracker will follow the indictment decision, each court setting, and the administrative outcome as the records land. The charge remains an allegation: Castillo is presumed innocent unless proven guilty.