One person has died and nine others are at the hospital a three-vehicle crash involving a bus in Jefferson County Monday.

The wreck happened just after 1 p.m. on a stretch of Highway 93 between CO 72 and CO 128. Two days later, Colorado State Patrol confirmed to 9NEWS that a passenger on the bus passed away.

That person was identified as 61-year-old Gregory Klein.

State troopers say the bus was part of the Developmental Disability Resource Center -- a nonprofit based in Lakewood.

Three people had broken bones and one had multiple fractures. Authorities originally said no one involved suffered any life-threatening injuries, but that is no longer the case.

Troopers say a blue Subaru heading north went into the southbound lane and hit the bus, which rolled onto its side. A red car that was headed south then hit the side of the blue car.

Dillon Mills, the driver of the blue car, was cited for careless driving causing injury. State troopers could not say if his charges would be upped in this case after a passenger passed away on Wednesday.

Mary Lynn and Eric Maes were on their way to the University of Colorado Boulder with their daughter when all of a sudden they were swerving off the road.

“You couldn't hear what anyone was saying because of the screaming and hollering,” Eric said.

When he managed to pull over, Eric, a retired Marine, ran to help the bus driver and passengers.

Troopers originally reported 26 people were on the bus, but later said 13 people were on the bus and 10 were injured.

All drivers involved are OK.

The highway was closed for hours as troopers cleaned up and investigated the wreck. It reopened around 3:45 p.m.