Fitness coach Richard Simmons passes away at 76, cause of death under investigation

The cause of death of Richard Simmons, an American fitness coach who promoted weight loss through his series of popular exercise videos, is now under investigation.

PEOPLE Magazine reported that Simmons died after celebrating his birthday, July 12, citing his longtime publicist Tom Estey.

Authorities said there was "no foul play" involved, but the Los Angeles Police Department later confirmed to the media outlet that the cause of his death "has since been deferred, meaning that an investigation and additional testing are needed."

According to PEOPLE Magazine, it can take up to three months "before a determination is made."

TMZ reported that Simmons was at his Los Angeles home when he passed away. Police responded to a call from a housekeeper on July 13 at around 10 a.m.

"The world has truly lost an angel," Estey told PEOPLE.

Simmons opened his gym Slimmons, formerly The Anatomy Asylum, in Beverly Hills in California in the '70s. There, he taught aerobics and motivational classes. His gym's success made him launch his television series The Richard Simmons Show, which aired during the early '80s. During the decade, his Sweatin' to the Oldies line of fitness videos rose to fame. He also launched his own fitness products.

Simmons was last seen in public in 2014, according to PEOPLE.