The Grand Prairie Fire Department is searching for a man believed to have drowned at Joe Pool Lake.
45-year-old Ed Thompson's wife tells NBC 5 he was training for a triathlon and went for a swim at about 5 p.m. Monday.
When he didn't return home for dinner she says she got worried, at around 7 p.m. she went to the park and found his car locked, with his wallet and mobile phone inside.
The woman called Grand Prairie police who then began to search for the man. A police dog traced Thompson's scent from his car to the shore, where his shoes were found and where he is believed to have entered the water.
Rescuers searched the area before suspending the search overnight. The search resumed Tuesday morning. As of 3 p.m., the man had not been located and the search is ongoing.
The woman told police that her husband only learned how to swim a couple of years ago.
NBC 5's Christine Lee contributed to this report.