A body found on Monday in the mountains of the rural city of Nantan, Kyoto Prefecture, has been identified as that of an 11-year-old boy who had been reported missing in the region, a police autopsy confirmed on Tuesday. 

Elementary school student Yuki Adachi had been missing since March 23. A three-week search culminated in the discovery of his body in the mountains on Monday evening. 

The autopsy revealed that the boy died sometime late last month but the exact cause of death remains unknown. There were no tears or other significant damage to Adachi’s clothing and no injuries from sharp objects on his body, according to NHK reports.Â