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Her mother's death still weighs heavily on her heart and mind, and Melissa Rivers wants answers, not money.

Melissa is expected to file a wrongful death suit against the person and entities that she believes are responsible for her mother's death. The late Joan Rivers died on Sept. 4 after going into cardiac arrest during a surgical procedure.

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E! News is reporting that Melissa has hired New York law firm Gair to explore a multi-million dollar wrongful death suit against the endoscopy clinic where the procedure was done.

"It's not about the money," a source told E!. "For Melissa, this is about getting an answer about why this happened and making sure it never happens again. The only way to get these answers is to file a lawsuit. Melissa wants answers -- not money."

As previously reported, Melissa stands to inherit over $100 million from her mother's estate. The legal action is almost as much about the principle of preventing these kinds of things from happening as it is finding out what happened in that clinic.

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"This shouldn't have happened," the source continued. "It was a completely treatable and avoidable complication."

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Melissa sees the lawsuit as part of a large effort to change policy on a "federal level" with regard to how private clinics function and are regulated, the source said. Melissa reportedly has concerns over what decisions were made on that fateful day, who made them and what precautions were taken.

Since her mother's death, Melissa has stayed out of the spotlight and mourned with her son, Cooper, but she has addressed her mother's fans via social media.

"As my son Cooper and I mourn the loss of my mother, we want to thank everyone for the beautiful cards and flowers conveying heartfelt messages and condolences, which continue to arrive from around the world and through social media," Melissa wrote on WhoSay on Sept. 17. "My mother would have been overwhelmed by the scope and depth of the love that people have expressed for her. It is certainly helping to lift our spirits during this time."