An 88-year-old man named William Marquardt has gone missing on foot in Colma, prompting a statewide Silver Alert covering San Mateo, Santa Clara, and San Francisco counties. Marquardt was last seen yesterday around 6:41 p.m. near Collins Avenue and El Camino Real, and authorities describe him as an at-risk missing person who needs to be found quickly.
The alert was posted by CHP - Alerts, the California Highway Patrol account responsible for sharing details and flyers on active statewide alerts. According to the bulletin, the California Highway Patrol activated the Silver Alert on behalf of the Colma Police Department, the small agency now leading the search. Marquardt is described as 5 feet 10 inches tall, weighing 210 pounds, with gray hair and blue eyes. He was last seen wearing a blue puffer jacket, an orange shirt, dark blue pants, and dark shoes.
SILVER ALERT - San Mateo, Santa Clara, and San Francisco Counties
— CHP - Alerts (@CHPAlerts) August 14, 2026
Last seen: Collins Avenue and El Camino Real, Colma@TownofColma
IF SEEN, CALL 9-1-1 pic.twitter.com/6AaAKK5wmD
A Compact Town With a Busy Crossroads
Marquardt's last known location sits at the intersection of Collins Avenue and El Camino Real, a stretch of State Route 82 that functions as a major commercial thoroughfare linking northern San Mateo County to Daly City, San Francisco, and South San Francisco, according to the Town of Colma. The corridor carries heavy traffic alongside commercial retail centers and regional bus routes, making it a high-visibility but potentially hazardous area for someone missing on foot. Colma itself is a small municipality of just 1.89 square miles, bordered directly by Daly City and San Francisco, and is widely known for its extensive cemetery grounds.
Public transit along El Camino Real includes SamTrans bus routes as well as connections to two nearby BART stations, giving anyone on foot rapid access across San Mateo and San Francisco counties, per the town's own transportation information. Colma also runs subsidized ride programs for seniors, though it remains unknown whether Marquardt used any such transit or ride service after he was last seen.
A Small Department Leaning on State Resources
The Colma Police Department, headquartered at 1199 El Camino Real, operates with roughly 15 patrol officers and sergeants covering the entire town, according to the Town of Colma. That modest staffing level is part of why local departments like Colma's coordinate with the California Highway Patrol's Emergency Notification and Tactical Alert Center, or ENTAC, which operates 24 hours a day out of Sacramento to evaluate missing person cases and launch multi-county alerts once local resources have been exhausted. Seniors aged 60 and older make up about 12% of Colma's roughly 1,700 residents, according to municipal demographic data, even as the town's overall population has trended younger over recent decades.
California's Silver Alert system traces back to Senate Bill 1047, enacted in 2012, which set the legal criteria requiring local agencies to verify a missing person's peril and exhaust local search resources before requesting statewide notification. The program was later expanded under Senate Bill 1127, effective January 1, 2015, broadening eligibility to missing individuals with cognitive or developmental impairments regardless of age; the original law had applied only to seniors 65 and older.
Why These Searches Move Fast
Research highlighted by the Alzheimer's Association and cited by the Fisher Center for Alzheimer's Research Foundation estimates that about 60% of people living with dementia or memory impairment will wander away from care at least once during their illness, a statistic that underscores why law enforcement treats missing senior cases with urgency. It remains unknown whether Marquardt has a diagnosed cognitive condition or a documented history of wandering, and the alert itself does not specify a medical cause for his disappearance.
The case echoes another recent Bay Area search: last Sunday, the CHP issued a Silver Alert covering San Francisco and San Mateo counties for 65-year-old Jason Chen, who had dementia and disappeared on foot in San Francisco, with family members telling KION that he was confused and at risk when separated from his caregivers. That alert, which Hoodline covered as a missing Bayview man's case, came just days before Marquardt's disappearance in neighboring Colma.
Anyone who sees William Marquardt is urged to call 911 immediately. No further details about the circumstances of his disappearance or any ongoing search efforts have been released.
