The Belgian Olympic Committee says swimmer Fanny Lecluyse "was sent home before the end of the games after an incident of inappropriate behaviour."
Belgian media reported that 20-year-old Lecluyse had returned to the athletes village appearing drunk at 3:30 a.m.
The team says Lecluyse left on Aug. 3. Two days earlier, she placed sixth in a 200-meter breaststroke heat won by Rebecca Soni of the United States.
Lecluyse's departure was confirmed after the Belgian team sent home cyclist Gijs van Hoecke. He was photographed looking intoxicated and unable to walk while leaving a London nightclub.