The Los Angeles Fire Department said Monday that Richard Simmons died of apparent natural causes even as an investigation into his death at home on July 13 continues.

The report is a preliminary finding after Simmons was discovered on the floor of his bedroom the day after his 76th birthday by his housekeeper.

The Los Angeles Police Department was called in after the Medical Examiner's Office deferred the case, prompting an investigation that will take up to three months.

Foul play was not suspected, but the Robbery Homicide Division was called to the scene because of Simmons' high profile.

The story

Simmons's housekeeper told police that he had fallen in his bathroom on his birthday but refused to seek medical treatment as she advised him to do.

She helped him get to his bed and he was found on the floor the next morning.

A source said Simmons reported feeling dizzy before he fell, but another source said he didn't appear to be injured after the fall.

Simmons had been out of public life for a decade prior to his death, and he attributed that to health reasons.

He had knee surgery that might have prevented him from continuing to lead the high-energy workout sessions fans had come to expect, and also had a bout with skin cancer that appeared to be resolved after it was removed.

His later years

Simmons had a habit of calling people undergoing cancer treatment and giving them a pep talk to encourage them, according to reports.

In an interview a few days before his birthday, his first since 2014, Simmons acknowledged that his fans missed him.

"I know people miss me," Simmons told People. "And you know what? I miss them, too. But I'm able to reach them through phone calls… and through emails."

Though he had a reputation for not leaving his house, he admitted that he sometimes did.

"I do leave the house sometimes," Simmons said. "But I'm in disguise."