As family, friends, celebrities and the world continue to mourn the untimely loss of Joan Rivers, more answers are coming out about the cause of her death.

According to the New York Daily News, the beloved comedienne went to outpatient clinic Yorkville Endoscopy on Aug. 28 to have a routine endoscopy -- but a doctor also performed a biopsy on her vocal chords, a procedure that should not have been done outside of a hospital, medical experts have revealed.

It was during the biopsy that Rivers' air supply was cut off, and she was rushed to Mount Sinai hospital and was put on life support. She was soon put into a medically induced coma and died after being taken off life support on Sept. 4.

Rivers' doctor reportedly asked the clinic if he could use their instruments, when the clinic's doctor allegedly noticed "something" on her vocal chords.

"He asked and they let him," the source told the Daily News. "A huge no-no." The source added that Rivers only signed off on the endoscopy -- not the biopsy.

The Daily News reports that while there is no criminal investigation of the clinic, the State Health Department is looking into the facility.

R.I.P., Joan Rivers.

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