A Sioux City man has been charged with stabbing and strangling his two stepdaughters during a ritual at their home.

Lawrence Douglas Harris Senior is charged with two counts of first-degree murder for the deaths of eight-year-old Alysha Suing and ten-year-old Kendra Suing.

Firefighters responded to a fire at the home Sunday and found the children in their smoke-filled second-story bedroom.

Police Lieutenant Marti Reilly says Harris had been performing "some strange ritual" but wouldn't provide more details.

Authorities say Harris had told them he had been casting a spell that had gone bad and that the spell could have severe consequences.

Reilly says the girls' mother was at work at the time.

The investigation is continuing. Harris is being held in the Woodbury County Jail under two million dollars bond.