North Carolina ? Investigators cast doubt Monday on accounts given by the father and stepmother of a missing 10-year-old whose battles with bone cancer left her with a prosthetic leg and hearing aids in both ears.

A search warrant revealed Monday that police dogs had detected the smell of human remains on cars belonging to the couple. Hours earlier, the police chief said investigators were having trouble finding anyone outside the household who had seen Zahra Clare Baker alive in the last few weeks.

The warrant filed in a Hickory court didn’t indicate that police found any remains in their search Sunday. It said the dogs detected the smell on a sedan and SUV.