BOISE, Idaho (AP) — Nearly all of the teenagers aboard an Idaho YMCA camp bus that rolled on a winding highway late last week have been released to their families, police said Monday.

Troopers are continuing to investigate the cause of Friday’s crash, which sent all those on the bus to local hospitals, Idaho State Police said in a statement.

Police said previously that 11 passengers were hospitalized, seven in critical condition, following the crash. The bus was carrying about 30 campers and staff back to Boise from the Treasure Valley YMCA’s camp at Horsethief Reservoir.

Police said Monday that injury updates would not be provided.

Troopers are working with the bus company to access pertinent information related to the crash, police said Monday. The bus driver was treated at a hospital and released, police said over the weekend.

The YMCA had contracted with Caldwell Transportation for the bus service. The Associated Press left messages with the company on Monday seeking comment.

The overturned bus blocked a local route, State Highway 55 along the Payette River, causing a massive traffic jam.

The scheduled camp session for this week was canceled so staff can cope with the emotional trauma of the crash, Treasure Valley YMCA officials said earlier.

“The Treasure Valley Family YMCA would like to thank the many individuals in our community for reacting quickly with heroic support of our campers and staff involved in the accident,” the Y said on Facebook. “We’re grateful for your continued thoughts and prayers as we work to support those involved.”