Updated 12:30 p.m. | Posted 11:42 a.m.
A truck driver hauling a boulder that dislodged and crashed into a car Monday killing two people has been arrested and is in the Dakota County jail pending charges, Rosemount police said Thursday.
Sixty-seven-year-old Karen Christiansen and her 32-year-old daughter, Jena Christiansen, were killed late Monday afternoon when their Toyota Avalon was hit by the estimated 800-pound boulder.
Rosemount police said they tracked down the commercial vehicle's owner and identified and arrested the driver in Inver Grove Heights. MPR News typically does not name suspects who are arrested for a crime until they are charged.
Investigators used images from surveillance video at the nearby Flint Hills refinery to identify the truck, said Rosemount Police Chief Mitchell Scott.
"What's sad is this could have been prevented, 100 percent could have been prevented, if that load had been secured," Mitchell said.