MINNEAPOLIS (WCCO) — The driver of a truck that dislodged an 800-pound-boulder that killed a mother and her daughter has been arrested.

Joe Czeck, 33, did not stop at the scene of the accident in Rosemount on Monday. As WCCO’s Kate Raddatz shares, the tragedy is a reminder to drivers to secure your load.

It took four fireman just to roll the boulder. It’s the same rock that police say came flying off Joe Czeck’s dump truck Monday. He was heading south on Rich Valley Road in Rosemount.

“It’s evident to us that it was not secured in the back of the vehicle,” Rosemount Police Chief Mitchell Scott said.

Karen Christiansen, 67, and her 32-year-old daughter Jena were headed north on the road. The truck went over a railroad crossing and the boulder came off, tumbled and struck the family’s car.

The women died at the scene.

“It’s very traumatic for the families. We don’t see this type of accident every day,” Scott said.

Investigators figured out the truck, shown here in this photo taken shortly after the accident, belonged to Czeck Services, which lead them to the driver.

Rosemount Police Chief Mitchell Scott says the tragedy is a reminder of the law.

“You’re required by law to have whatever you are hauling secured in your vehicle. So if you have a lawn mower or an ATV, UTV inside, you are responsible to make sure it’s secure,” Scott said.

Even if an accident doesn’t occur, drivers can still be pulled over and given a ticket for unsecured loads.

“Things happen out of our control all the time, so take the extra time to make sure things are secure,” Scott said.

Czeck is being held at the Dakota County Jail. Charges are still pending.