A Pierce County Sheriff’s sergeant who was hired by the City of Langley in a police use-of-force investigation was arrested on suspicion of first-degree assault, according to the department.

Robert Glen Carpenter was booked into the Pierce County jail shortly after 2 a.m. Friday, KIRO News reported.

Carpenter billed himself as an expert in police use of force and one of the state’s top tactical instructors for law enforcement trainees.

Langley Mayor Tim Callison hired Carpenter earlier this year to review whether the former police chief, David Marks, used excessive force or violated policy in arresting a trespassing subject in November 2017.

Carpenter concluded that Marks’ actions were proper police tactics and that Marks used the minimum amount of force necessary in the situation.

Carpenter’s conclusions were at odds with accounts provided by a deputy with the Island County Sheriff’s Office and a Langley police officer, both of whom were at the scene. They alleged Marks used unnecessary force when handcuffing the suspect and caused him to fall face first on the ground.

Callison announced this summer that he was terminating Marks, but a settlement was reached in which Marks resigned his position.

Carpenter was suspended from duty in 2007 after he was arrested twice in one day in Chelan County for driving under the influence, KIRO reported.

Carpenter was one of two deputies with the Pierce County Sheriff’s Office who fired shots that killed a 36-year-old man in 2003. The man reportedly lunged at them with an automobile jack in 2003.

The shooting was ruled justified.

Glen Carpenter, an expert in use of force by law enforcement officers,demonstrates handcuffing techniques on former Langley police chief David Marks at a city council meeting earlier this year.