Off-duty Sonoma Co. sheriff's deputy kills mother of his children, then himself, police say

SANTA ROSA, Calif. (KGO) -- Authorities say an off-duty Sonoma County sheriff's deputy is dead after he fatally shot his ex-partner, who is also a sheriff's department employee, before taking his own life. It began Sunday night in Santa Rosa, when police and SWAT negotiators were called in, after neighbors called 911, reporting an incident of domestic violence.

Residents in Northeast Santa Rosa say their neighborhood was in lockdown around 7 p.m. for a manhunt.

"There were police officers coming into my cul-de-sac, there was a helicopter hovering for a few hours," said Christina Savala.

It began with a frantic 911 call from a neighbor in an apartment complex on the 4600 block of Quigg Drive.

"We got a call from a woman in an apartment complex stating that a male partner of a neighbor had come to her apartment and dropped off an infant, saying call 911 because the mother was hurt," said Santa Rosa Police Sergeant Patricia Seffens.

Police say that man was off-duty Sonoma County sheriff's deputy, Jeremy Lyle, 44, a ten-year veteran of the department. He is pictured on the department's Instagram page with his K9, Rappa.

"Officers made entry and located a deceased female victim 38 years old, and two additional young children inside the residence," Seffens said.

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The officers found Lyle's ex-partner, Mari Bonnici, on a couch in the living room with at least one gunshot wound. Twin toddlers were found unharmed in a back bedroom. Bonnici was a sheriff's department employee.

A short time later, about 7:30 p.m., police got notification that Lyle was parked at the Sonoma County Coroner's Office, where he refused to surrender.

"The negotiator with our negotiations team communicated on and off with Mr. Lyle until 2 a.m., unfortunately he took his own life with a single gunshot," said Seffens.

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"It's as bad as it get I can't even fathom if the children saw that, I can't even imagine," said Steve Schneider, who lives in Santa Rosa.

Police are now investigating a possible motive and any history between the couple.

"At this time, we have no reports of previous domestic violence," said Seffens.

The sheriff's department says it's mourning the loss of two beloved employees and sending condolences to their families.

The twins and the infant are all being cared for by family members, police said.

Bay City News contributed to this report