A Texas BMX legend has been found dead of a self-inflicted gunshot wound after allegedly shooting dead an employee in his bike shop during an argument.

Wesley Don Johle, 58, was discovered by police at his Rowlett home shortly after the body of James Kincheloe, 40, was found inside the Garland shop on February 16.

There was no sign of any forced entry. Surveillance footage from inside the shop showed 'enough probable cause' to suspect Johle, said Lieutenant Richard Maldonado of Garland police. 

Investigators are now trying to work out what happened in the moments leading up to Kincheloe's death. 

Johle was one of the most celebrated BMX racers in the U.S., with 50 national BMX titles to his name and over 500 career wins.

He retired in 1985 and opened the bike shop, which was owned by his mother.

In 2012, he was one of the first seven to be inducted into the Texas BMX Hall of Fame.

Kincheloe's wife and mother of his two young sons said the family has been left reeling following the sudden death. Daisy McKee said Johle was not a violent person, and was struggling to make sense of her husband's murder.

'I didn't know Don to be a mad, or sad, person,' she told WFAA, adding that her husband had worked at the shop for a decade.

McKee said the general manager of the store, Preston Hoeger, told her it seemed like the pair had got into a fight.

'Preston, the one who found him, his coworker, said the way he was when they found him looks like he was trying to wrestle the gun away from Don,' she said.

'Whatever happened, he was trying to stop it.'

She said their children keep on asking if their father is coming home, and miss riding to school on the bike with him.

'He was so much fun,' she said. 'He had a humor like nobody I've ever known.'

Police now hope to interview other employees to find out if there had been any recent tension between the two men.

A woman who works next door told Fox 4 she knew the men casually, and never heard of any problems at the bike shop.

She said that the lights were on at the bike shop when she left on the evening of February 15, which struck her as unusual as they normally closed before she did.

Johle was not just a talented BMX racer.

After his retirement from the sport, he took up jet ski racing and became a regional champion, and ranked as one of the top ten watercraft sports racers in the world.

He then took up driving, racing a Legend car - a smaller and cheaper fiberglass version of a NASCAR race car - and winning a championship at Texas Motor Speedway.

In 2018, Johle told Voyage Dallas website he felt fortunate to work in a sport he loved.

'I think the combination of hard work and dedication have played this biggest role in the success of our business,' he said.

'It's great to be able to make a career out of something you have a passion for and love doing.'