Police have questioned officials of Nihon University on a voluntary basis over a dangerous late tackle by one of its American football players during an intercollegiate game earlier this month, investigative sources said Tuesday.

The questioning was conducted by the Metropolitan Police Department on Monday. With a full-scale investigation into the Nihon University football team in sight, the police are likely to hear from key figures such as former head coach Masato Uchida and former assistant coach Tsutomu Inoue.

The focal point of the investigation will be whether the coaches had ordered the rough play in the May 6 game in Tokyo.

Taisuke Miyagawa, the 20-year-old player who injured quarterback Kosei Okuno of archrival Kwansei Gakuin University, explained last week that he was instructed by his coaches to "crush" him during the game, but the coaches denied it and blamed it on a miscommunication.

The injured American football player filed an official complaint with the police last week.