On February 6, 2021, at approximately 8:00 a.m., Montgomery County Police responded to the 6000 block of Olney Laytonsville Road (Route 108) for the report of a vehicle collision.

Upon arriving at the scene, deputies observed three cars which were involved in the accident, one of which was run off the road to avoid collision and the other two being involved in a head-on collision. As seen in the footage, Deputy Darren M. Popkin, an 18-year veteran of the force, was confronted by the suspect who caused the accident.

Within seconds of arriving, Deputy Popkin observed the suspect exiting his disabled vehicle, while wielding a large stick, where he then began threatening the secondary party involved in the accident. Approaching the suspect, Deputy Popkin attempted to use less lethal force, however his taser was ineffective toward the suspect.

Deputy Popkin continued to verbally command the suspect to drop the blunt object, however he did not comply. After striking Deputy Popkin numerous times with his blunt object, Deputy Popkin then discharged twelve shots from his service weapon, striking the suspect the chest. After subduing the suspect, Deputy Popkin began providing medical aid until paramedics arrived on the scene. The suspect, who was later identified as 52-year-old Kevin Costlow, was pronounced deceased at the scene.

After a thorough investigation, Mr. Costlow's toxicology reports came back negative for drugs or alcohol. At a later portion of the investigation, Costlow's brother Steve, as well as Kevin's wife were interviewed. Steve Costlow believed that Kevin had suffered a “psychotic break.” Steve also mentioned that Kevin had recently been involved in an automobile accident and was currently taking medication due to a previous neck injury.