A fatal shooting on the Bay Bridge early Monday morning caused a widespread shutdown of traffic as all eastbound lanes were blocked for hours while authorities conducted an investigation on the span.

Three eastbound lanes were reopened just after 6:30 a.m. Monday, “but due to congestion, it’s moving slowly.” said Officer Pedro Santiago, a California Highway Patrol spokesman. Westbound lanes were unaffected.

The shooting occurred at about 2:30 a.m. and involved three vehicles, according to CHP Officer Bert Diaz. The driver of a sedan traveling in the center lane heard a gunshot just before an SUV in the farthest right lane swerved and struck his vehicle. A third vehicle, for which no description was available, sped off.

The driver of the SUV, a black male adult, was killed and a white male adult was injured from the shooting. A third passenger was also injured but it was unclear whether the injuries were from the shooting or the crash, Diaz said.

The driver of the sedan was able to talk to the CHP but may have suffered minor injuries.

All of the injured parties in the SUV were taken to San Francisco General Hospital.

No further information on the shooting was immediately available.

Drivers were stuck behind the closed section of the bridge for hours. On Twitter, motorists could be seen getting out of their cars, walking around and stretching in the lanes, as motorcycles turned back.

Michael Cabanatuan and Demian Bulwa are San Francisco Chronicle staff writers. Email: mcabanatuan@sfchronicle.com, dbulwa@sfchronicle.com Twitter: @ctuan @DemianBulwa