Police have tracked down a 19-year-old male high school graduate in the Tohoku region who may have been involved in seeking answers online for questions from entrance examinations held in February at four prominent universities while the tests were in progress, investigative sources said Wednesday.

Police have already established that the same mobile phone was used during the four separate exams at Kyoto and Doshisha universities in Kyoto, and Waseda and Rikkyo universities in Tokyo, the sources said.

The police plan to interview the youth, who took the exams this year on his second chance to enter a college after graduating from a high school in Yamagata Prefecture last March, on a voluntary basis, the sources said.