The NYPD and Medical Examiner's office are investigating the death of Joan Rivers, who died days after complications from an outpatient procedure, and now it seems that an ill-advised biopsy may have contributed to her demise. The Daily News reports, "The Aug. 28 biopsy at Yorkville Endoscopy, an E. 93rd St. clinic that usually only deals with digestive issues, caused Rivers' vocal chords to seize — a condition doctors call a laryngospasm — cutting off her air supply, the source said."

Rivers, 81, was at the clinic for an unspecified procedure (reports say she wanted to see why her voice was hoarse). The NY Times reports, "Dr. [Lawrence] Cohen, her doctor, is a prominent gastroenterologist, with many publications and panels to his name. Based on his specialty, other doctors have surmised that she might have been treated for acid reflux, which could have affected her voice." From the Daily News:

Rivers’ doctor — who identified himself as an ear, nose and throat specialist — asked if he could use their instruments when the clinic’s doctor noticed "something" on Rivers’ vocal chords, according to the source.

“He asked and they let him,” the source said. “A huge no-no.” The source added that the “Fashion Police” star had only signed off on an endoscopy — not the far more dangerous biopsy of her vocal chords.

The News' source said, "A biopsy like that should only be done in a hospital setting... If she had been in a hospital when it happened, she might have been okay."

It's unclear if there was an anesthesiologist present during Rivers' procedure; the Times points out, "Dr. Cohen argued in a 2007 paper in the journal Gastroenterology that gastroenterologists should be able to perform endoscopic procedures on basically healthy people without an anesthesiologist present, a position that has provoked debate in the medical world."

Rivers was put in a medically-induced coma and died on September 4.