Waukesha County Sheriff's Department, Wisconsin
End of Watch: Thursday, June 22, 1978
Age: 50
Tour of Duty: 24 years
Badge Number: Not available
Cause of Death: Gunfire
Date of Incident: June 21, 1978
Weapon Used: Officer's handgun
Suspect Info: Sentenced to life
Sergeant O'Brien and Deputy Michael Geszvain were shot and killed when a prisoner gained control of Deputy Geszvain's service weapon.
The officers were standing in court with the prisoner when the incident occurred. The suspect exchanged shots with another deputy on the first floor of the courthouse. Sergent O'Brien was transported to a local hospital, where he succumbed to his injuries the following day.
The suspect used an attorney as a shield to leave the courtroom. He was apprehended after taking a social worker hostage and forcing her to drive to Madison, Wisconsin. The man was sentenced to two counts of life in prison. He was up for parole in 2000, and it was denied for another 20 years.
Sergeant O'Brien was a United States Army and Marine veteran. He had served 24 years with the Waukesha County Sheriff’s Department. He is survived by his wife and seven children.