MISSOULA, Mont. -

The Montana Highway Patrol continues to investigate the cause of a fatal car accident near Ronan.

Ronan residents Iva Skelton, 45, and Karen Jore, 56, were killed when their vehicle ended up in an irrigation ditch along Canyon Mill Road between Pablo and Ronan.

Lake County officials told KERR-AM that a passer-by spotted a vehicle upside down in the canal just after 6 a.m. Monday.

Investigators believe the accident may have occurred between 11 and 11:30 p.m. Sunday.