One of the country’s top sprint canoeists has been banned from competition for eight years for spiking a younger rival’s drink with an anabolic steroid, causing him to fail a doping test, the Japan Anti-Doping Agency said Tuesday.

The incident took place at the national canoe sprint championships last September in Komatsu, Ishikawa Prefecture, where the perpetrator, 32-year-old Yasuhiro Suzuki, and the victim, 25-year-old Seiji Komatsu, were both competing, according to the Japan Canoe Federation.

The two had been considered among the top prospects to represent Japan at the 2020 Tokyo Olympic Games and were teammates at last year’s canoe sprint world championships in the Czech Republic, where Suzuki finished 24th in the men’s K1 5000-meter. Komatsu was a member of the K4 500-meter crew which reached the semifinals.

An investigation by the canoe federation found that Suzuki drugged his rival ahead of Olympic team selection in order to cause his disqualification.

After Komatsu tested positive, Suzuki admitted to spiking his rival’s drink with a muscle-building supplement containing the banned steroid methandienone.

The incident is Japan’s first case of an athlete failing a doping test due to deliberate contamination, according to the doping agency, which handed down the eight-year ban.

Komatsu had his temporary ban for the failed test lifted, but his results at the national championship were voided.

In its investigation into the incident, the canoe federation found that Suzuki had made repeated attempts to sabotage other competitors, not only Komatsu, by such means as stealing equipment used in training and competition. It has recommended Suzuki’s expulsion from the federation.

“An incident of this nature is unheard of in the history of sports in Japan and it is very disappointing,” Sports Agency Director Daichi Suzuki said.

At a news conference in Tokyo, Japan Canoe Federation Managing Director Toshihiko Furuya apologized for the incident, which has dealt a blow to the image of Japanese sports ahead of 2020 when Tokyo will host the Olympics.

“It is a significant loss for Japanese people who have spent many years building up sportsmanship as a virtue,” Furuya said.

Police in Ishikawa Prefecture are reportedly investigating the incident after Komatsu filed a complaint.