Cause of death of Richard Simmons is under investigation

The cause of Richard Simmons’ death is under investigation, the Los Angeles Police Department confirmed to PEOPLE.

The fitness guru died one day after celebrating his 76th birthday, his longtime press agent Tom Estey told PEOPLE on Saturday, July 13. Police told PEOPLE that “no foul play was involved.”

The medical examiner’s office said Simmons’ cause of death is now unknown, meaning an investigation and additional tests are required. It may take up to three months to determine the cause of death.

Simmons died at his Los Angeles home and no foul play was suspected, TMZ reported. The newspaper added that authorities responded to a call from a housekeeper around 10 a.m. local time on Saturday.

“The world has truly lost an angel,” Simmons’ spokesperson told PEOPLE.

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Simmons recently told PEOPLE it was a “good” feeling to turn 76. “I’m grateful to be here and to be alive for another day,” he said. “I’m going to spend my birthday doing what I do every day, which is help people.”

Two days before his death, Simmons also spoke to PEOPLE about his legacy, admitting that he did not consider himself an icon or a legend.

“I never saw myself as a celebrity,” he said in his last interview. “People don’t know that. I’m actually a shy and somewhat introverted person. But when the curtain goes up, it’s a different story. I’m there to make people happy.”

Simmons continued, “But the praise I get via email. I mean, today we probably answer over 100 emails. And they say, ‘I’m your biggest fan.’ And I just write back and say, ‘Don’t say that, because I’m a human being like you. And I know you do good things too.'”

Although he remained humble, Simmons admitted that he was still “proud” of himself and his influence on how people talk about fitness and nutrition.

Simmons, who hasn’t been seen in public since 2014, told PEOPLE that he misses his fans as much as they miss him.

“I know people miss me. And you know what? I miss them too. But I can reach them by phone … and email,” he said. “And I leave the house sometimes. But I’m in disguise.”