Four people were sent to the hospital after a five-vehicle crash on the McKees Rocks Bridge on Friday night.
Allegheny County officials say nine people were involved in the crash, which occurred just before 9 p.m. Friday.
The bridge was shut down and reopened about 2:30 a.m. Saturday.
Two people went to the hospital in critical condition and two others had serious injuries.
The cause of the crash is under investigation by Allegheny County Police Collision Reconstruction Unit.
Anyone with information on the wreck can call the Allegheny County Police tipline at 833-255-8477.
