The Tokyo Family Court said Wednesday a 16-year-old boy should stand criminal trial for the brutal 2005 slaying of a 15-year-old girl in her home in the Tokyo suburb of Machida.

The Hachioji branch of the family court is sending the case back to prosecutors with instructions that, based on psychiatric tests, the boy is mentally fit to be tried as an adult.

The boy basically confessed to killing Yua Koyama, who went to the same high school as him and reportedly spurned his overtures of affection, during his juvenile trial that began Dec. 15, after prosecutors sent the case to the family court earlier the same month.

The boy, whose name is being withheld because he is a minor, allegedly broke into Koyama's Machida apartment last Nov. 10, took a knife from the kitchen and stabbed her 50 times.