UPDATE: 2 killed when boulder hits car

(WCCO) UPDATE: There's new information this morning on a deadly boulder crash near the Twin Cities this week: Police have arrested the man they believe was driving the landscaping truck from which an 800-pound boulder dislodged.

They used surveillance video to track down the driver who they say failed to properly secure the boulder that fell out onto a road and killed a mother and daughter.

A 33-year-old Hastings man is in jail in connection with the accident.

ORIGINAL STORY: A Minnesota mom and her daughter are dead after a landscaping boulder fell off a truck and hit their car. It happened Monday afternoon in Rosemount.

Police believe the 800-pound boulder fell from the truck that was crossing some railroad tracks, then bounced and rolled into oncoming traffic.

They say the boulder went completely through the vehicle that Karen and Jena Christiansen were in. The truck driver didn't stop, but police believe they've identified the company.