Police looking for motive after man opens fire in workplace and kills two coworkers

Police are searching for a motive after a man shot three co-workers during an altercation at a northern Virginia business on Wednesday, before taking his own life along an interstate highway amid a police standoff.

Marvin Grant, 37, opened fire at an equipment rental business, killing two co-workers and leaving a third hospitalized, Manassas Police Chief Doug Keen said at a news conference.

Grant fled in a vehicle, but detectives were able to track his phone to the Harrisonburg area, Keen said.

Keen identified the two workers who died as Richard Lamont, 48, and Christopher Serrano, 33.

A third worker was in stable condition at a hospital in Fairfax, the chief said.

Manassas is about 30 miles (50 kilometers) southwest of Washington, D.C.

Grant later pulled over on I-81 in Augusta County and fatally shot himself during a standoff with Virginia State Police. A state police statement said troopers did not use force.

The motive behind the shooting remains unclear, according to Keen.