"The swimmer (Tomita) stole a camera from a South Korean journalist. CCTV revealed the swimmer had put the camera in his bag," Tsuyoshi Aoki, head of the Japanese swimming team, told a press conference, reports Xinhua.
"He has confessed to stealing the camera but interrogation is still on. He has not been booked officially.
"He has been expelled from the team effective immediately. He will have to find his own way back to Japan. Further consequences of the act will be decided upon in Japan," added Aoki.
Tomita, 25, won the gold medal in the men's 200-meter breaststroke at the 2010 Asian Game but failed to win a medal in Incheon.