A lawsuit over a Sonoma County Sheriff’s Office employee’s 2025 killing by her estranged partner, a deputy who later died by suicide, alleges he abused and supplied steroids to coworkers while exhibiting increasingly violent behavior that authorities failed to address.A federal civil rights laws uit filed in September accuses Sonoma County, the city of Santa Rosa, and two Sheriff’s Office employees of failing to intervene before Jeremy Lyle, 44, killed Mari Bonnici, 38, and himself on August 10, 2025, as the Press Democrat reported last month. The suit also alleges authorities failed to properly investigate after the killings. It was filed on behalf of the couple’s three children, twin daughters who were 2 at the time and a son who was 1, who now live with their paternal aunt and uncle in Napa County.Lyle and Bonnici reportedly began dating in 2018, had twins in November 2023, and registered as domestic partners in April 2024. Their relationship reportedly became increasingly abusive, and they separated shortly after their son was born in October 2024.The 21-page complaint also alleges that Lyle’s use of anabolic steroids contributed to his increasingly erratic and violent behavior. Per the Press Democrat, the sheriff’s deputy was also allegedly manufacturing and selling steroids to other department employees, including personnel in command positions, and Santa Rosa police allegedly failed to investigate transaction records found on his phone after his death.According to the Chronicle, the lawsuit identifies trenbolone, a steroid developed to increase muscle mass in cattle, as one of the substances Lyle and other department personnel allegedly used.His brother, Geoffrey Lyle, repeatedly contacted the Sheriff’s Office in the months before the killings, warning that Jeremy was suicidal and could pose a danger to himself and others, according to the complaint.The following month, Geoffrey Lyle contacted the sheriff’s non-emergency line to report that his brother was in crisis and should be relieved of duty, per the Press Democrat. During a subsequent call with Sergeant Tommy McNeil, one of the defendants, Geoffrey also reported that Jeremy had struck Bonnici during an argument and locked her outside while he remained inside with their children, according to the lawsuit.Lyle’s brother repeatedly sought help after the deputy expressed suicidal thoughts, but the lawsuit alleges that McNeil and Captain Orlando Rodriguez, another defendant, failed to intervene. Lyle later allegedly threatened another deputy’s wife with a gun, attacked a Sheriff’s Office employee, and placed a tracking device on Bonnici’s car. He remained on duty with access to firearms.Bonnici filed to end their domestic partnership in June 2025. According to the Press Democrat, a week before her death, she called 911 to report threats from Lyle, but the lawsuit alleges that the operator told her she and Lyle “needed to grow up,” and no Santa Rosa police officers responded.Izaak Schwaiger, an attorney for the children, blamed department leadership and a failure to hold employees accountable. The lawsuit also points to a pattern of “never to arrest one of their own for domestic violence.”Sonoma County, the Sheriff’s Office, and the Santa Rosa Police Department declined to comment on the lawsuit. Sheriff’s Office Sergeant Juan Valencia said an internal administrative review was complete, but its findings would remain confidential.Related: Planned Memorial at SFPD HQ For Slain Retired Deputy Chief Ann Mannix Canceled Due to Outsized Response ...read more read less