Photo/Illutration A car taking the suspect to prosecutors leaves Motofuji Police Station in Tokyo’s Bunkyo Ward on Jan. 17. (Takayuki Kakuno)

Investigative sources said the 17-year-old suspect of a stabbing spree near the University of Tokyo on the day of unified university entrance examinations had planned it in advance.

Three people, including two entrance-exam takers, were stabbed in the attack near the university’s campus in the capital’s Bunkyo Ward on Jan. 15.

After the second-year high school student from Nagoya was arrested on suspicion of attempted murders, he told police that he “was planning it in advance,” investigative sources said.

He is also suspected of scouting out the location where the crime would take place in advance in the early morning on the day of his stabbing spree.

Police sent him to prosecutors on the morning of Jan. 17.

He is suspected of having tried to kill a female high school student, 17, and a male high school student, 18, who were going to take the entrance exams, by stabbing them in their backs with a knife near the university’s Yayoi campus around 8:30 a.m. on Jan. 15.

A 72-year-old man nearby was also stabbed and is suffering from serious injuries.

According to investigative sources, the youth admitted to the charges just after his arrest and provided his motives for the crime, along with background information.

But after a while, the suspect clammed up and has remained silent about his case, although he still makes small talk with the investigators.

The teen said right after his arrest that he left Nagoya by overnight bus on the night of Jan. 14 and that he arrived at JR Tokyo Station around 6 a.m. on Jan. 15, sources said.

He was quoted by police as saying that after he arrived in Tokyo, he “went to see the site for the attack once in the early morning” and “changed from my private clothes into a school uniform.”