Police on Tuesday raided the office of an elite computer engineer who was arrested a day earlier on copyright-related charges for developing and offering software that allows people to swap movies and video games.

Detectives searched the office of Isamu Kaneko, a 33-year-old research assistant at the prestigious University of Tokyo, and left with two boxes of documents and other evidence, a university spokesman said on condition of anonymity.

Kyoto Prefectural Police, who arrested Kaneko on Monday, refused to comment.