The Tokyo High Court has upheld a decision to institutionalize a 13-year-old girl for pushing a 5-year-old boy from an apartment building in Tokyo in June, sources said Wednesday.

Her lawyer said during the appeal trial that she did not intend to kill the boy, who was seriously injured in the fall.

But presiding Judge Toshio Yamada said in handing down the decision that 13-year-olds know a person can die if they fall from a four- or five-story building, according to the sources.

The judge said the girl's denial of the allegations cannot be trusted as she had drastically changed her statements, adding that she has a strong tendency to break social rules, blame others and lie.

He said she needs to receive systematic support for rehabilitation as she has been troubled about her family and committed the crime because she had not fundamentally changed after receiving counseling from a child consultation center.

The decision also allows the institution for delinquent children where she will be held for two years to confine her for up to 180 days.

The Supreme Court has already rejected the girl's appeal of the confinement.

The girl pushed the boy June 22 after letting him sit on the handrail in an outdoor stairwell between the fourth and fifth floors of a building in Tokyo's Shinjuku Ward, according to the family court.

The boy landed in some bushes and survived.

The girl cannot stand criminal trial because she was under 14 at the time of the incident. Held for attempted murder, she initially admitted pushing the boy but reversed her account in August during an interview with a psychiatrist.