WEST FARGO, N.D. (AP) - Police searched through the night for a 15-year-old girl and her 20-month-old niece, saying they believe the older girl took the toddler.

Amy Doll and her niece, Shara Doll, were last seen about 10:30 p.m. Monday, when Amy was babysitting the younger girl, authorities said.

"We have no idea why she took the 20-month-old, what her reasoning was. There was no food, diapers or anything with the baby," Police Detective Greg Warren said.

Warren said authorities do not believe the girls were abducted.

"We don't have any indication of that right now," he said early Tuesday.