Respects have been given at funeral of mma trainer Shawn Tompkins (vid)

Well-known mixed martial arts trainer Shawn Tompkins died of a heart attack, says his brother-in-law Sam Stout.

Tompkins, 37, died in his sleep Sunday. An autopsy was performed Monday and while results are not yet available, Stout, who is also one of Tompkins UFC fighters, says it was a heart attack.

“I don’t know what to say,” Stout says. “It’s not supposed to happen to a healthy 37-year-old person. Who would think he had to get checked out for that?”

The funeral service is Friday at 1 p.m. at West Park Church, 955 Gainsborough Rd., London.

A spokesperson for the Oxford detachment of the OPP said Tompkins’ death was “not suspicious.”

He died at a friend’s house in Ingersoll.

“Shawn’s family had a history of heart disease,” said Tompkins’ manager Gary Ibarra of Athletic Management & Representation Group (AMR).

“Shawn had an enlarged heart and blocked arteries,” Ibarra said. “No one had any idea.

“It really doesn’t matter how much you exercise and what kind of shape you are in. That’s why everyone is in such shock.”

Tompkins was AMR’s second client and Ibarra said he was probably the most important at the time because it gave his company legitimacy.

“But that’s secondary,” he said. “Shawn had become a friend.”

The closely knit local MMA community is still reeling over the sudden death. Even though Tompkins was based in Las Vegas his career began in Tillsonburg and London and several current fighters have been with him since they were young.