Medics and King County sheriff's deputies responded to the scene, at SW 136th Street and Ambaum Boulevard SW, at about 8:15 p.m. Sunday after receiving a report of a bus involved in a serious crash.

Arriving there, they found a Snoqualmie Casino bus had completely crashed through the wall of a vacant building. The bus driver had sustained severe head injuries. She was taken to Harborview Medical Center, where she is listed in critical condition.

No one else was on board the bus that was marked "Snoqualmie Casino Express."

The King County sheriff's office says the bus struck the building after first colliding with an SUV at an intersection. A man and woman in the SUV were taken to Highline Hospital with minor injuries.

Sgt. John Hall says witnesses also reported seeing a woman and boy running from the SUV.

Investigators are looking into whether alcohol was involved in the crash.