Dukic, 28, was competing in an 800-meter swim at the CrossFit Games in Fort Worth's Marine Creek Lake when, around 8 a.m., something went terribly wrong, and he vanished beneath the water.
A search was immediately launched, and about two hours later, first responders recovered his body from the lake. The CrossFit Games later confirmed the heartbreaking news of an athlete's death.
Dukic, from Serbia, was an experienced CrossFit competitor, ranking third in his country and 88th in the world. Just last night, he posted on Instagram, encouraging fans to tune in to today's event, which tragically turned out to be his final post.
Seven firefighter units responded to the search, and 10,000 spectators from around the world witnessed the event, which sadly had to be halted.