Orange County Sheriff's Department, California
End of Watch: Monday, October 24, 1988
Age: 31
Tour of Duty: 7 years
Badge Number: Not available
Cause of Death: Aircraft accident
Date of Incident: October 24, 1988
Weapon Used: Not available
Suspect Info: Not available
Deputy Sheriff Mark Tonkin was killed in a helicopter accident while working on a multi-agency narcotics task force along the United States border.
A suspicious vehicle was spotted in a canyon on a remote access road in the Mountain Springs Grade area. The UH-1H helicopter began to descend when its rotor blades struck power lines and caused it to crash in the foothills of the Laguna Mountains.
Also killed in the accident were Investigator Michael Davis of the Riverside County Sheriff's Department, Deputy Roy Chester of the Los Angeles County Sheriff's Department, Sergeant Richard Romero of the Imperial County Sheriff's Department, Deputy Mark Tonkin of the Orange County Sheriff's Department, and the three California National Guard crew members operating the flight.
Deputy Tonkin had served with the Orange County Sheriff's Department for seven years. He was survived by his wife and parents.