HASTINGS, Minn. — A man is being held in the deaths of a mother and daughter were killed when an 800-pound (360-kilogram) boulder fell from the truck that police say he was driving and smashed into their car in suburban St. Paul.

Jail records show 33-year-old Joseph Czeck is being held on suspicion of criminal vehicular homicide and criminal vehicular operation in the crash Monday in Rosemount, Minnesota. Czech is due to appear in court Friday.

Sixty-seven-year-old Karen Christiansen and her 32-year-old daughter, Jena Christiansen, died at the scene.

Czeck, of Hastings, was arrested after police found his landscaping truck Wednesday night. Rosemount Police Chief Mitchell Scott says it isn't clear whether Czeck was aware that the boulder had fallen.

Jail records don't list an attorney who can speak on his behalf.