Japanese couple arrested after 33-year-old daughter weighing 42 pounds dies

(CNN) A couple in Japan have been arrested after their emaciated adult daughter was found dead in a windowless room where she had apparently been locked for at least 15 years.

The daughter, 33, weighed less than 42 pounds -- about the average weight of a 4-year-old -- when her body was discovered Saturday, police said. She appeared to have died from exposure to the cold, police said.

The couple, who live in Osaka, kept their daughter in an unheated structure next to their house, according to police. The room measured about 39 square feet and the pair locked it from the outside, police said.

Her parents fed the woman one meal a day and forced her to drink water through a tube, police said.

The couple, who were arrested Tuesday and remain in police custody, said they confined their child because she was mentally ill and violent.

The official reason given for the arrests is abandoning a corpse. Under the law Osaka police have 23 days from the time of the arrest to decide whether to press charges. The defendants' first court appearance would occur several months after any formal charges.