A Halloween night that started at a Millbrae party has ended with serious felony charges against a 38-year-old San Mateo man. Prosecutors say Guillermo Pirirpulic is at the center of an alleged gang rape that began in a field at Martin Luther King Jr. Park and continued inside a vehicle. The incident is dated to the early hours of Nov. 1, 2025, after the party in Millbrae, and authorities say they are still looking for a second, unidentified suspect as the case moves through the courts.
San Mateo County District Attorney Steve Wagstaffe told reporters that the woman had taken a ride-hail from the Halloween party in Millbrae and was walking home while intoxicated when she was brought to a field at Martin Luther King Jr. Park. There, an unidentified man allegedly raped her. Wagstaffe said Pirirpulic later met that man in the park parking lot, took the victim to his car and allegedly raped her again. The woman reportedly woke up at home with no memory of how she got there, and a rape kit later yielded sperm cells, according to the San Mateo Daily Journal.
Where It Happened
Martin Luther King Jr. Park is a City of San Mateo recreation site at 725 Monte Diablo Avenue that features open fields, sports courts and a community center. The layout, with fields next to parking areas, is public information and lines up with the general area investigators have referenced in their timeline. Details and a park map are available from the City of San Mateo.
Charges And Court Status
Prosecutors have charged Pirirpulic with kidnapping for the purpose of sexual assault, two counts of gang rape and digital penetration. He pleaded not guilty at an arraignment on Feb. 24, according to the District Attorney's office. Prosecutors say DNA found in the rape kit helped support the charges, and the complaint alleges Pirirpulic raped the victim after meeting the other man at the park. As reported by the San Mateo Daily Journal, the case is proceeding in San Mateo County Superior Court while investigators continue to follow leads.
Investigation And Next Steps
Wagstaffe said investigators are actively working to identify the other man described in the complaint and have asked anyone with information to come forward. Victims and witnesses can contact the San Mateo County District Attorney Victim Services Division for support, compensation assistance and court accompaniment. Criminal cases in the county are handled through the San Mateo County Superior Court, and local authorities say they will provide updates as the investigation continues. The DA's victim-services page lists contact details and resources for those affected.
Legal Implications
The charges are serious felonies that could carry lengthy prison sentences if Pirirpulic is convicted, but prosecutors must prove every element beyond a reasonable doubt. Pirirpulic remains presumed innocent while the case moves forward, and the District Attorney's office has said it will present its evidence at upcoming hearings. Anyone with information is being urged to contact local police or the District Attorney's office.
