RICHLAND, Wash.–UPDATE 2:48 P.M.

The Richland Police Department said Trooper Sarah Clasen was the trooper involved in the collision and is now in custody.

UPDATE 12:52 P.M.:

The incident took place on SR 240 near Horn Rapids, according to the Richland Police Department . The trooper involved will be held on a 72-hour hold.

An investigation is still ongoing and the Benton County Prosecutor's Office will review the case upon completion, according to RPD.

A Washington State Patrol trooper was involved in a fatal collision on Saturday.

The trooper was driving in a personal vehicle off duty during the incident and was taken into custody by the Richland Police Department, according to a WSP press release. An independent fatal collision investigation is being conducted by RPD.

No other injuries resulted from the incident, according to the release.

This is an ongoing story and will be updated and more information comes in.