Texas officials are trying to determine how a man died during a challenging and at times chaotic obstacle race called the "Original Mud Run" last weekend, but race organizers are going ahead with another mud run for next month.

Tony Weathers, 30, died during Fort Worth's Original Mud Run Saturday and Fort Worth police said an autopsy is being conducted. The homicide division is waiting for the medical examiner's ruling to see if there will be a follow-up investigation.

Weathers' death is the first fatality in the 14 year history of the race, and officials said the next Original Mud Run in Houston on May 26 will continue as scheduled.

The Original Mud Run is set up as a 5K or 10K obstacle course.  The 5K consisted of 3.1 miles and 18 obstacles and the 10K was 6.2 miles with up to 30 obstacles.  The obstacles contain water and mud.

Weathers started the course at 2 p.m. and one of the first obstacles was to swim across the Trinity River.  Friends on a bridge to cheer him on and take pictures never saw him cross, according to ABC affiliate WFAA. When Weathers' girlfriend didn't see him cross the finish line, she told race organizers he was hours late.

"The fire department went out Saturday evening around five o'clock when we were first notified," Timothy Hardeman, engineer and spokesperson for the Forth Worth Fire Department told ABC News.

"By the time we narrowed down where he might have been by eliminating any other possibilities, we had to suspend the search at this point because of darkness," he said.  Dive crews found a body at 11 a.m. in the Trinity River Sunday morning.

"I just don't know how it happened. He's strong enough to pull himself out of that water," Lynetta Moore, Weathers' personal trainer, told WFAA.  "I don't know if he was trampled, tangled, but it doesn't make sense. Totally out of character for someone with that level of athleticism. Something went wrong."

"We are profoundly saddened by the passing of Tony Weathers," said DFWRUNS spokesman Eric Lindberg.  "We express our deepest condolences and sympathy to his family and friends."

"With any of our obstacles that involve river crossings or swimming we provide alternate routes, swim assist devices, guide ropes, floating platforms and certified life guards," Lindberg said.

In addition, he said that during the registration process and before each wave of racers took off, participants were told to skip or use the alternate route if they had any doubt they could complete that leg.

Mud Run racers, however, described a chaotic scene at the river crossing.

"From my perspective, the lifeguards at the first river crossing were over-burdened with people that should have never been in the water," said Jim March of Colleyville, Texas, in a Facebook message to ABC News.

"I then saw a lifeguard at the first platform pulling a swimmer to the platform screaming for the strong swimmers to get to the outside," he said.  "Next I heard more people calling for help, and she rushed off to save them. As I continued on, I saw the lifeguard from the opposite shore dive in and swim the length to assist the first lifeguard."

March said he did not feel unsafe and is aware of his limits.  He informed the race announcer of what he saw in the river and the announcer stressed to the racers not to attempt the swim without being a strong swimmer.

In a comment on the Facebook page, participant Tim Green of Texas said he and his son had a problem with the water crossings.

"The 'lifeguard' told him 'you aint a man if you can't make it across,' so as a result he pushed through," Green wrote about his son crossing the first water obstacle.  "He was 'man' enough to know not to cross on the second one.  He felt like he had no options for the third one and had to cross."

Green said he also had a difficult time crossing and considers himself a good swimmer.

All participants must sign a consent and waiver before participating.  When signing the forms a participant agrees to assume risks of personal injury and not hold the parties mentioned in the forms responsible for loss or damage including death.