"Apparently the mom had given her a lot of duties," Miami County Sheriff Ken Roland said. "It was too much for a 12-year-old and she snapped."
Authorities began looking for the girl, her 8-year-old brother and her 6-year-old sister early Monday after their mother called 911. The 29-year-old woman said she had awakened with her bed on fire and discovered her children and car were missing.
Police called the woman's cell phone and spoke to the 12-year-old, sheriff's Sgt. Gary Glassburn said. The girl told officers she and her siblings had been kidnapped and forced to drive south while the abductor followed in another vehicle.
The girl had driven about 15 miles when police talked her into stopping just south of Peru, about 70 miles north of Indianapolis. The children were found unharmed.
Investigators determined there was no abduction and the girl had stolen her mother's car.
The 12-year-old was being held in a juvenile detention center on charges of arson and attempted murder, said police, who did not release the names of those involved. The other two children were released to their mother.