A 19-year-old boy was found starved to death early Monday at his home in Hannan, Osaka Prefecture, police said.
Investigators said Shohei Kitamura was found dead at 4:10 a.m. by his 48-year-old mother. They said they were questioning the woman on suspicion of abandoning her responsibilities as a guardian.
Police were alerted to the situation by ambulance staff. They said the 182-cm-tall youth weighed 32 kg -- the average weight of a 9-year-old boy.
The woman said her son had not had anything but water for the past three weeks, according to police.
"Even when I made meals like ramen noodles, he refused to eat. I didn't take him to a hospital because it would cost money," she was quoted as saying.
According to investigations, Kitamura was found dressed in a shirt and trousers and lying on his back on a plastic sheet on the floor of his room. An autopsy put the time of death at around midnight, police said. There were no external injuries on the body, they said.
Kitamura began living with his mother in Hannan after graduating from a high school in Naha, Okinawa Prefecture, in March.
He was unemployed. His mother held a cleaning job.
Neighbors said that they did not seem to have any problems getting along with each other, and that they were both the quiet type.