Hickory police said Tuesday they had canceled the Amber alert for Zahra Baker, The Charlotte (N.C) Observer reported. The arrest of her stepmother, Elisa Baker, on a felony obstruction of justice charge came the day after police had named her as a "person of interest" in the girl's disappearance.
"We are handling this as a homicide investigation," Chief Tom Adkins said at a late-morning news conference.
Adkins said the 42-year-old stepmother had admitted under questioning Monday night she wrote the ransom note. She then asked for an attorney and refused to answer more questions.
Police said no one except immediate family had seen the girl in weeks, the newspaper said.
Since her disappearance was reported Saturday, police found a ransom note and dogs detected possible human remains in a sport utility vehicle parked at the family's home.
Friends and relatives told the Observer Zahra and her father Adam Baker came to the United States from Australia.
They moved into a rented house in Hickory six weeks ago along with Zahra's stepmother, Elisa Baker, who met Adam Baker online.
They described Zahra as an exceedingly polite child who lost her leg below the knee to bone cancer. She also suffered from a hearing loss.
Adkins had said Monday it was unlikely Zahra ran away because her hearing aid was in the house.