Joan Rivers' daughter has hired a high-profile New York City law firm, in what reports are saying is the first step of her filing a costly lawsuit against the endoscopy clinic that performed a procedure on her mother, ultimately leading to her death. The law firm Gair, Gair, Conason, Steigman, Maloof, Bloom & Rubinowitz confirmed that the comedienne's daughter, Melissa Rivers, had contracted with them to investigate the circumstances surrounding her death. Reports say Ms. Rivers is looking to sue Yorkville Endoscopy in Manhattan, where her mother underwent a minor throat procedure on Aug. 28, for wrongful death.