Joan Rivers' daughter Melissa Rivers is preparing to file a medical malpractice and wrongful death lawsuit.

The TV producer, who was devastated when the 81-year-old comedienne died from ''predictable'' surgical complications while undergoing a minor operation on her vocal cords last month, has reportedly hired top US law firm Gair, Gair, Conason, Steigman, Mackauf, Bloom & Rubinowitz to represent her in a multi-million dollar court battle against the Yorkville Endoscopy Clinic in Manhattan, New York City and the doctors that treated Joan there before her death on September 4.

A source close to the 46-year-old star, who inherited $100 million from the late 'Fashion Police' host, told gossip website TMZ.com that she retained the firm on Tuesday (28.10.14), but the suit won't be filed for another month to give her lawyers time to gather phone logs, medical records and other documents.

Her legal team also sent letters to various people involved in the fatal medical procedure on Tuesday, asking them not to destroy any records relating to Joan's treatment.

The New York City Medical Examiner's Office recently released a statement confirming that Joan's brain had been starved of oxygen after she suffered cardiac and respiratory arrest on the operating table.

Following the news, Melissa wrote on Twitter: ''In response to NYC's Medical examiner's report, we continue to be saddened by our tragic loss. No further comment at this time.''