Joan Rivers Death Lawsuit: Without Biopsy, Medical Examiner Can't Determine If Death Was 'Preventable' [VIDEO]

There was never an autopsy performed on Joan Rivers, which means her true cause of death may never be revealed.

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The comedienne died on Sept. 4 after complications from a routine procedure at New York City's Yorkville Endoscopy. Investigators believed doctors may have performed an unauthorized throat biopsy.

Sources connected to the New York City Medical Examiner told TMZ on Oct. 19 that daughter Melissa Rivers requested doctors not perform an autopsy. New York law will follow Melissa's wishes, as long as no criminality is involved in the death.

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The Medical Examiner concluded that a "predictable" complication in the procedure caused her death, not the Propofol administered. However, "predictable" can also mean "preventable."

A source close to the investigation revealed to TMZ on Oct. 17 that the procedure was already completed when Rivers suffered brain damage from lack of oxygen, which is what officials were saying was her official cause of death.

Because there were no "underlying causes or contributing factors" involved, this could mean someone was at fault. The source questioned if anyone was monitoring her oxygen levels during the procedure. Another source said an autopsy may reveal a puncture in the throat or other trauma.

While the Medical Examiner may have concluded that a "predictable" complication stopped the flow of oxygen to the comedian's brain, causing irreversible damage, without an autopsy, investigators cannot determine if her death was preventable.

Keywords here are "predictable" and "preventable."