If found guilty, student who used phone in university entrance exams will be first in Japan to earn criminal record for cheating.
The 19-year-old student is driven away from a police station in Sendai, where he was arrested on suspicion of cheating on an entrance exam at Kyoto University by posting test questions online with his mobile phone.
For a few brief days he was the most wanted person in Japan.
Police launched a manhunt, while newspaper editorials decried an age of lost innocence. Warnings were issued that the perpetrator might not have acted alone.
The crime: using mobile technology to cheat during entrance examinations to some of Japan's most prestigious seats of learning.
On Thursday night police arrested a 19-year-old preparatory school student after tracing the mobile phone he used to its subscriber, his mother. The student, whose name is being withheld because he is a minor, has admitted soliciting help online during entrance exams for four universities.
Using the name "aicezuki", he posted mathematics and English questions on Yahoo! Japan's chiebukuro (pearls of wisdom) bulletin board during exams at Kyoto and three other universities last month, reports said.
Answers appeared within minutes from more than 20 of the estimated 27 million people who use the site in Japan every month. Police found several answers on the site that closely matched those written on the student's exam papers.
Given the speed with which he posted a complex maths problem, investigators believe he photographed the questions using a model of mobile phone that enables users to disable the shutter sound.
Yahoo! Japan, an affiliate of the US internet company, said it would co-operate fully with the police investigation.
Police closed in on the suspect days after tracing the user to Sendai in northern Japan. He was arrested near the city's main railway station after his parents told police he had failed to return home the previous evening.
As well as being disqualified from the exam process, he now faces charges of fraudulent obstruction of business, a crime punishable by up to three years in prison or a maximum fine of 500,000 yen (£3,700).
If found guilty the teenager would be the first person in Japan to earn a criminal record for cheating.
Japanese media quoted him as saying he had acted alone. "I just wanted to pass the exam," he said.
While some said the case highlighted the pressures of the "exam hell" Japanese students must endure to enter higher education, the student, for all his resourcefulness and reported contrition, is unlikely to gain much sympathy.
The education minister, Yoshiaki Takaki, said his behaviour was unforgivable. "This deed has greatly damaged the credibility of university entrance exams, which should be fair and just. It is truly regrettable," he said.
The episode has dominated TV news since the allegations came to light last weekend. Newspaper editorials bristled at the thought that the meritocratic values – whether real or imagined – on which Japan's top universities pride themselves had been compromised.
"This is a heinous act that undermines the fairness that should be the basis of the university entrance exam system," the Yomiuri Shimbun said.
With another round of university entrance exams later this month, education authorities are considering a ban on mobile phones at exam sites, a measure South Korea introduced in 2004 in response to widespread cheating.
