Joan Rivers dead at 81

Comedy legend Joan Rivers has died at the age of 81. She went into cardiac arrest on Aug. 28, and had been on life support at New York's Mount Sinai Hospital.

"It is with great sadness that I announce the death of my mother, Joan Rivers. She passed peacefully at 1:17 p.m. surrounded by family and close friends," her daughter Melissa Rivers said. "My son and I would like to thank the doctors, nurses, and staff of Mount Sinai Hospital for the amazing care they provided for my mother."

E!, where she headed up the snarky talk show "Fashion Police," released a statement of condolence.

“She’s been a much beloved member of the E! family for over 20 years and the world is less funny without her in it," they said. "Today our hearts are heavy knowing Joan will not be bounding through the doors.”

The NYC Medical Examiner's Office told FOX411 it will be investigating the cause and manner of Rivers' death. “The death has been reported to us and the Medical Examiner’s Office is investigating," a rep said.

The Dept. of Health is also looking at the endoscopy clinic where she went into cardiac arrest during a minor throat procedure. “It’s a full investigation of the matter," their rep said.

A native of New York, Rivers originally entered show business with the dream of a theatrical career, but comedy became a way to pay the bills while she auditioned for acting roles.

"Somebody said, 'You can make six dollars standing up in a club,'" she told The Associated Press in 2013. "And I said, 'Here I go!' It was better than typing all day."

After proving herself in comedy clubs as a rarity — a woman comedian — Rivers was a smash on her first booking on "The Tonight Show Starring Johnny Carson" in 1965. "God, you're funny," Carson told her.

She never stopped writing, testing and fine-tuning her jokes.

"The trouble with me is, I make jokes too often," she told the AP in 2013, just days after the death of her older sister. "I was making jokes yesterday at the funeral home. That's how I get through life. Life is SO difficult — everybody's been through something! But you laugh at it, it becomes smaller."

She had also faced a true crisis in the mid-1980s. Edgar Rosenberg, her husband of 23 years, committed suicide in 1987 after she was fired from her late night talk show, which he produced. The show's failure was a major factor, Rivers said. Rosenberg's suicide also temporarily derailed her career.

"Nobody wants to see someone whose husband has killed himself do comedy four weeks later," she told The New York Times in 1990.

Comedy was not only her calling, but her therapy, as she turned her life inside out for laughs, mocking everything from her proclaimed lack of sex appeal ("My best birth control now is just to leave the lights on") to even her own mortality.

"I have never wanted to be a day less than I am," she insisted in a 2013 interview. "People say, 'I wish I were 30 again.' Nahhh! I'm very happy HERE. It's great. It gets better and better. And then, of course, we die," she quipped.

In 2009, Rivers emerged as the winner of NBC's "The Celebrity Apprentice." A documentary, "Joan Rivers: A Piece of Work," premiered in theaters in 2010.

The entertainer logged a half-century in show business and gave rise to red carpet commentary — and the criticism that often accompanies it. Her signature red carpet query "Who are you wearing?" became commonplace.

Rivers most recently worked as a host of "Fashion Police" on E! network co-starred with her daughter, Melissa, on the WEtv reality show, "Joan & Melissa: Joan Knows Best?"

"Cooper and I have found ourselves humbled by the outpouring of love, support,
and prayers we have received from around the world," Melissa Rivers stated. "They have been heard and appreciated.

"My mother's greatest joy in life was to make people laugh. Although that is
difficult to do right now, I know her final wish would be that we return to laughing
soon."

The Associated Press contributed to this report.