On Saturday, 28-year-old Air Force Staff Sergeant Antonio Tucker, along with his young daughter and the little girl's mother, were on a rental boat on Lake Mead near Las Vegas when things went wrong.
Antonio's mother Catujita Baker received a call from her son's girlfriend.
"He decided to go for a swim and the winds picked up and pushed the boat away from him. She threw him a buoy or life raft and he could not grasp it because the winds were pushing him away, pushing the boat away," Catujita said.
The young woman called 911 and told authorities she did not know how to operate the boat.
She kept trying to stay in contact with Tucker who continued to drift away.
"He was getting tired, he told her he didn't know if he was going to make it and she saw him go under," Catujita said.
Tucker was with an Air Force unit based in Nevada that maintained remotely piloted aircraft or drones.
His mother says he was proud of his job and had been stationed at bases around the world including Afghanistan.
Authorities at Lake Mead, the largest reservoir in the US, continue to look for Tucker's body.