King County Sheriff’s Office deputy faces assault charge

A King County Sheriff’s Office deputy faces a misdemeanor assault charge after King County prosecutors say he intentionally punched a suspect seat-belted and handcuffed inside a patrol vehicle that kicked him.

Prosecutors filed a charge of assault in the fourth degree against Matthew Wayne Good on Oct. 17 for a March 5 incident.

The Des Moines Police Department’s investigation of the incident found Deputy Good punched David K. Teson six to eight times in the chest in the back of a patrol vehicle.

Captain Koby Hamill of the King County Sheriff’s Office Internal Investigation’s Unit contacted the Des Moines Police Department on March 7 to request the department conduct an outside independent investigation into the incident, according to an affidavit.

Law enforcement arrested Teson after dispatching to a domestic violence call in the City of Seatac.

According to an affidavit of probable cause, statements from additional law enforcement at the scene stated Teson kicked Good multiple times prior to Good pushing Teson and punching him multiple times.

Of the nine additional King County Sheriff’s Office deputies responding to the scene, two identified the incident as an unreasonable use-of-force, one declined to state whether Good’s use-of-force served as reasonable, one stated the use-of-force was reasonable, and five reported not observing the use-of-force incident, according to the affidavit.

Through interviews with the nine deputies at the scene, the Des Moines Police Department’s investigation of the incident established Good struck Teson when he was under arrest, handcuffed, and seat-belted in the backseat of a King County Sheriff’s Office patrol vehicle.

According to an email from Casey McNerthney, director of communications for the King County Prosecuting Attorney’s Office, deputies involved in the incident reported the “alleged criminal conduct.”

In interviews with six Puget Sound firefighters identified as responding to the incident location on the night of the incident, the firefighters described not seeing Good’s use-of-force. Having interacted with Teson, they described Teson’s behavior and demeanor as erratic.

According to McNerthney’s email, the department initially contacted the criminal division of the SeaTac City Attorney’s office for review of the case.

After an attorney at the SeaTac attorney’s office cited a potential conflict of interest prosecuting a SeaTac police officer, the department filed the case in King County District Court.

According to the affidavit, the King County Prosecuting Attorney’s Office retained R. Scot Haug, a use-of-force expert to review the incident.

Haug determined Good’s use-of-force to be “unreasonable and not a necessary use-of-force,” according to the affidavit.

The King County District Court scheduled for Good’s arraignment on Oct. 5 at the Maleng Regional Justice Center.

Teson faces a felony charge of assault in the third degree for assaulting an officer.