Prosecutors have filed charges of criminal vehicular homicide against a Hastings man suspected of driving away after a 1,100-pound boulder fell off his truck and killed two women passing by in a car.

Police say that the driver pulled over after the boulder rolled onto the car, but then he drove away.

Last Monday on Rich Valley Boulevard in Rosemount, a mother and daughter were out driving. They were not thinking about that this may be their last moments alive.

Their Toyota Avalon was heading north, when a truck came over a railroad crossing and rolled the boulder on top of their Avalon killing instantly, Karen Jean Christiansen and her daughter Jena Helene Christiansen.

Investigators found out that it was a truck belonging to Czeck Services that was responsible for dropping the boulder. 33-year-old Joe Czeck, owner of Czeck Services, was arrested Wednesday. He was driving the truck at the time of the tragedy.

A co-worker of Karen Christiansen who worked at Dakota County Technical College told KSTP that she was"a sweet person who went out of her way to help students. "She touched hundreds of lives as people strived to improve themselves and help their families," Marlo Teal said.

Teal added, "We are devasted and hope her family can find peace after this tragic loss of mother and daughter."

Joe Czeck Dakota County Jail Photo