Police investigation of a serious auto crash caused a three-hour closure of Folsom's Rainbow Bridge Sunday.

Heavy rain and possible excessive speed are blamed for a collision at 5:06 p.m. on Riley Street near Scott Street, not far from the bridge.

A Seattle man, Sean Malone, 39, was seriously injured and hospitalized at Mercy San Juan Hospital in Carmichael, said Folsom Police Department Sgt. Andrea Chapman.

"He was in critical condition, on a ventilator last I heard," said Lt. Perry Albers.

Slightly injured were Folsom's James Tait and passengers in his vehicle, Chapman said. They were treated and released at the hospital.

Darkness had fallen when Malone's northbound 1999 Porsche Carrera may have crossed a centerline on Riley Street, according to Chapman. Investigators have not yet fixed a cause of the crash, she said.

Malone's car collided with a 2008 Chevrolet Blazer being driven southbound by Tait.

Alcohol was not involved as a circumstance, Albers said.

The Police Department sent specially trained collision investigators to the scene for an extensive probe that included a detailed mapping of the roadway in the vicinity of the crash, Albers said.

"We kept the bridge closed for the Major Accident Response Team members to work, because traffic was already re-routed and was getting lighter as the evening progressed," Albers said.

The Telegraph’s Roger Phelps can be reached at rogerp@goldcountrymedia.com, or post a comment at folsomtelegraph.com