Gwinnett County police released new details Thursday in a hit-and-run that left a pedestrian dead and shut down a major highway for hours Wednesday.

Investigators are searching for a white work van with a roof rack that left the scene, Gwinnett police spokesman Cpl. Ryan Winderweedle said.

“It is unclear at this time the van’s involvement and we are asking for the driver to come forward and/or any other witnesses to contact investigators,” he said.

The incident happened at the intersection of Centerville Highway and Bethany Church Road, Gwinnett police said in a tweet. According to the preliminary investigation, the pedestrian was not in a marked crosswalk and was crossing Centerville Highway when they were struck by a vehicle.

All southbound lanes of Centerville Highway were closed for more than an hour while authorities investigated. Police reopened the road about 9:30 a.m.

Anyone with information about the van’s whereabouts is asked to call police at 678-442-5653.