Police say a retired sergeant shot his deputy chief wife and their daughter, then himself, inside a quiet Marin County home.
Story Snapshot
- Sheriff’s investigators reported a suspected double murder-suicide at a Strawberry Circle home.
- Three adults were found dead: Kevin Mannix, his estranged wife Ann, and their daughter Katherine.
- Multiple 911 calls came in around 5 p.m.; one caller escaped before deputies arrived.
- San Francisco’s police chief echoed the murder-suicide description given by Marin deputies.
What Happened Inside The Mill Valley Home
Marin County deputies responded to a burst of 911 calls just after 5 p.m. at a home in Strawberry, an unincorporated area near Mill Valley. Deputies entered the residence and found three adults dead: retired San Francisco police sergeant Kevin Mannix, 68; his estranged wife, retired deputy chief Ann Mannix, 65; and their 24-year-old daughter, Katherine. The Marin County Sheriff’s Office said the preliminary investigation points to a double murder-suicide with a male suspected shooter.
San Francisco Police Chief Derrick Lew told the public that Marin investigators described the case as a murder-suicide involving retired members of the department. Local coverage reported the same sequence and noted the family’s law enforcement ties. Officials said the response followed reports of gunfire inside the home. Detectives processed the scene and began interviews with neighbors. The Sheriff’s Office also managed road closures around Strawberry Circle while securing the block.
How Investigators Framed The Case So Quickly
The Sheriff’s Office used clear language about a suspected murder-suicide after seeing the scene, finding all three deceased, and learning a male was the suspected shooter. That language matters. It signals a working theory, not a jury verdict. Investigators often make an early classification when scene patterns match known domestic violence cases. That can guide evidence collection, next-of-kin support, and public safety updates while lab work and autopsies follow standard timelines.
Reporters cited the time-specific trigger behind the fast response: multiple 911 calls at about 5:03 p.m. One caller inside the home reportedly escaped before deputies arrived, which added urgency to the search for survivors and threats. Dispatch logs, body camera files, and autopsy findings usually fill in the gaps later. But the initial scene gave deputies enough to inform the community and begin trauma services for those close to the family.
Who The Mannix Family Were In Public Life
Kevin and Ann Mannix both served San Francisco for years in uniform. Ann rose to deputy chief and was known in local policing circles. Kevin retired as a sergeant. Their daughter, Katherine, was 24. The family’s service record drew messages of shock and grief from former colleagues. The San Francisco Police Department and local media described the event as a suspected murder-suicide and honored the victims’ lives with remembrances from friends and peers.
A retired San Francisco police sergeant killed his wife – also a former police officer – and their 24-year-old daughter in Mill Valley in what is believed to be a murder-suicide. Here's what we know. https://t.co/1yauh5mYJc
— KTVU (@KTVU) October 13, 2026
Coverage placed the event in Strawberry, a coastal enclave known for quiet streets and steep home prices. The contrast sharpened the shock. Neighbors told reporters they heard gunfire and saw a heavy police presence lock down the area. The Sheriff’s Office urged patience during the evidence process while keeping the public informed. Leaders also reminded residents of counseling options and crisis lines, which is now a standard step after traumatic local events.
Why This Tragedy Fits A Wider Domestic Pattern
Most murder-suicides in the United States involve domestic relationships and happen in the home. A national review found about six in ten cases involve intimate partners, and about eight in ten occur at a residence. That pattern matches the Marin case as described by deputies and the San Francisco chief. Public health tracking also shows that many homicides grow from arguments or partner conflict, which helps explain why sheriffs quickly treat these scenes as domestic violence first.
Families deserve the full truth and final records. The preliminary label does not replace autopsies, ballistic tests, and scene reconstructions. It sets a practical lane for the work. When a home turns into a crime scene with three dead and a likely shooter among them, detectives must move fast to protect evidence, inform the public, and care for survivors. That approach respects both common sense and the duty to confirm the facts before closing the case.
Hard Lessons For Safety And Community
Domestic violence hides in plain sight, even in safe, wealthy neighborhoods. Friends hear tension. Loved ones see stress. Early help can save lives. Communities should press for strong crisis response, forceful enforcement of threats, and fast access to protection tools. Faith groups, employers, and neighbors can share hotline numbers and support safe exits. Law enforcement leaders should continue clear, prompt briefings that balance public need with family dignity and a careful, evidence-first investigation.
Local leaders now face the long tail of grief: funerals, tributes, and a home that stands as a reminder. The facts, as officials have shared them, are stark and devastating. The right next step is steady support for the family circle and a clean, final case file. That honors the victims, guides prevention, and helps a shaken community steady itself for the days ahead.
Sources:
foxnews.com, hoodline.com, nypost.com, vpc.org, cdc.gov
