Japan expelled top swimmer Naoya Tomita from the Asian Games and promised Saturday that he would face strict punishment after admitting he stole a journalist's camera at the Incheon pool.
South Korean prosecutors are now considering whether to press charges and the 25-year-old will have to pay for his own ticket back to Japan, officials said.
Japan's chef de mission Tsuyoshi Aoki apologised for Tomita's conduct at a press conference.
"I want to offer my sincerest apologies that such a regrettable incident has happened amid the excitement of the Asian Games," said Aoki.
Japan swimming bosses promised Tomita, who was taken away by police on Friday, would face tough sanctions.
"I'm shocked that this sort of thing could happen after the Japanese team performed so well in the pool," said Japan Swimming Federation director Masafumi Izumi. "He will be dealt with severely."
Japanese swimming coach Norimasa Hirai added: "The other swimmers are in shock."