Joan Rivers' daughter Melissa has sought out a top law firm to look into the circumstances of her mothers death.

According to reports, Manhattan firm Gair, Gair, Conason, Steigman, Mackauf, Bloom & Rubinowitz was asked to take on the case on Tuesday (28 October) and has already started gathering evidence.

The legal agency will investigate what happened at the clinic where the legendary comedian stopped breathing during a routine throat procedure.

The doctors who carried out the surgery will also be named, sources said.

It has been reported that Melissa is planning to file a medical malpractice and wrongful death lawsuit.

There is expected to be at least a month of collecting evidence but according to reports, letters are already being sent out to the medical centre to request it does not destroy any records relating to the fatal medical procedure.

Other documents, including private phone logs, have also been requested.

It is unclear how much compensation will be claimed in the case if a lawsuit is officially filed but Melissa - who reportedly inherited over $110m from Rivers' estate - is said to be concerned about ensuring that any foul play is brought to light rather than financial gain.

The Fashion Police host died on 4 September after going into cardiac arrest at the clinic on 28 August. She was 81.