A 56-year-old man who was arrested over leaving knives on Prince Hisahito's classroom desk at a Tokyo school has told investigators he had intended to stab the 12-year-old, investigative sources said Wednesday.

Kaoru Hasegawa admitted to leaving the knives and criticized Japan's imperial system after being apprehended on April 29 for allegedly trespassing on the grounds of Ochanomizu University Junior High School, which is attended by the nephew of Emperor Naruhito, according to the sources.

The prince and his fellow students were outside the classroom when the two knives were left, at around 11 a.m. on April 26.