Retired SFPD Sgt. Kevin Mannix fatally shot his estranged wife and their adult daughter before killing himself at the family's Mill Valley home, authorities believe.
Marin County deputies raced to a $2 million home in the Strawberry neighborhood of Mill Valley, California, shortly after 5 p.m. Sunday after reports of gunfire from inside the house.
Within minutes, deputies made contact with a reporting party who exited the residence safely. After securing a perimeter, they went inside and found three people dead. Officials determined there was no ongoing threat.
The Daily Mail reported the Marin County Sheriff's Office preliminary finding: a suspected double-murder suicide involving three people, with a male suspected shooter.
Sources told the San Francisco Chronicle that Kevin Mannix, 68, shot and killed his estranged wife, Ann Mannix, 65, and their youngest daughter, Katie Mannix, 24, before killing himself. Police believe that same sequence of events.
Investigators have not shared the circumstances that led up to the shooting. Autopsies were scheduled for Tuesday. Detectives processed the scene as the Bay Area absorbed another sudden loss inside a law-enforcement family.
Ann Mannix was not a side figure in San Francisco policing. She was a former deputy chief and a known trailblazer in the department.
The San Francisco Police Officers Association said she became the first woman to join and lead the SWAT team. She later rose to lead the Field Operations Bureau in 2018 and the Special Operations Bureau in 2019.
San Francisco Police Chief Derrick Lew addressed the department on Sunday after the deaths.
Chief Lew said:
"It is with heavy hearts that we share the news of the passing of Ann and Kevin Mannix."
He added a direct appeal to the rank and file:
"Please keep their family in your prayers. BSU is available to all members who may need it during this difficult time."
BSU is the department's support resource for officers under stress. The chief's message framed the deaths as a blow to the whole force, not only one household in Mill Valley.
On Monday, the San Francisco Police Officers Association posted a statement on Facebook about the suspected murder-suicide.
The association wrote that the case “has left our entire SFPD family reeling.” It described Ann's career in plain terms and tied Kevin's service to officers who still remember him on the job.
The association said:
"Ann Mannix was a trailblazer in our department, becoming the first woman to join and lead the SWAT team, and rising to lead both the Field Operations and Special Operations Bureaus."
On Kevin, the union noted:
"Many worked alongside Kevin during his 27 years of dedicated service at Taraval Station and beyond."
Taraval Station is a San Francisco Police Department station on the city's west side. Kevin spent a long stretch of his career there before retiring.
The association closed on the daughter as well:
"To see their lives, and the life of their 24-year-old daughter Katie, end in such a horrific and senseless manner is a burden that weighs heavily on every officer, active and retired."
Katie Mannix was 24. She was identified as the couple's youngest daughter. She died in the same home as her parents on Sunday evening.
Kevin Mannix retired from the San Francisco Police Department in June 2018 after 27 years as a sergeant. In a retirement letter to Taraval Police Station, he described a future that sounds ordinary and hopeful on the page.
He wrote:
"I am looking forward to a new life of leisure with family and friends. But I am a little saddened by the thought of not seeing all of you every day or at community events."
He continued:
"I will miss you all. Believe me, that is not a trite generalization... I leave the SFPD, but I am taking your friendships with me forever."
That letter is now part of the public record of a career that ended in retirement and, years later, in a sheriff's callout to the family home. The marriage was described as estranged. No charging documents apply after a suspected murder-suicide. No motive has been released.
The Marin County Sheriff's Office said deputies arrived within minutes of the gunfire reports, got the reporting party out, locked down the perimeter, and entered the home. They found three deceased people and declared the scene clear of an active threat.
The sheriff's office stated:
"Within minutes, deputies arrived on scene and made contact with the reporting party, who safely exited the residence. After securing a perimeter, deputies entered the home."
Officials also stated:
"The preliminary investigation indicates a suspected double-murder suicide involving three individuals. The suspected shooter is male."
That is the working theory tied to Kevin Mannix. Full autopsy findings were still ahead as of the Tuesday schedule. Weapon details beyond reports of gunfire inside the house have not been laid out in the available official statements.
Mill Valley sits in Marin County, north of San Francisco across the bay. The home's reported value underscores a comfortable private setting, not a street corner or a random target. The violence stayed inside the family residence until neighbors or a reporting party heard shots and called for help.
San Francisco's police leadership and its officers' union moved quickly to name Ann and Kevin, mark Katie's death, and point stricken colleagues toward support. The department lost two former members and a young woman connected to both in a single evening.
Private violence destroyed three lives in one Bay Area house, and a department that polices a major city was left to mourn people it once trusted to keep order.
