Police released a grainy picture on Tuesday of the van that authorities believe struck and killed a 63-year-old man near the Broadway Tunnel in San Francisco.

Officers found Sun-Choi Law, who lived near the scene of the crash, just before 6 a.m. Friday in the road on Broadway, west of Powell Street, after someone reported a body in the street, said Officer Albie Esparza, a spokesman with the San Francisco Police Department.

A witness saw the van heading south on Powell Street and making a right turn onto westbound Broadway, where it hit Law and kept going, police said in a statement. Police are still investigating the circumstances surrounding the collision, including whether Law was in a crosswalk or had the green light.

They describe the vehicle as a white van with no windows on its sides, possibly a 1997-to-2002 Ford Econolin.

Those with information on the location of the van can call police at (415) 575-4444.

Hamed Aleaziz is a San Francisco Chronicle staff writer. Email: haleaziz@sfchronicle.com Twitter: @haleaziz