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PITTSBURGH (KDKA/AP) – A former University of Pittsburgh medical researcher wants a new trial in the alleged cyanide death of his wife claiming, among other things, her donated liver suggests she wasn’t poisoned as prosecutors contend.

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Dr. Autumn Klein died in April 2013. Her husband, Dr. Robert Ferrante, was found guilty in the fall of 2014 of first-degree murder. He is currently serving life in prison with no chance for parole.

Prosecutors said Ferrante put cyanide in his wife’s energy drinks to poison her.

But now, his defense lawyers are saying there is new proof that didn’t happen.

Ferrante says he got a letter in prison from a 62-year-old man who received Klein’s liver in a transplant after her death.

Ferrante’s lawyer’s say Klein could not have suffered cyanide poisoning and then gone on to successfully donate a liver. The liver would have been irreparably damaged if she had been poisoned.

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Attorneys are now appealing to a three-judge superior court panel to get a new trial and say the recipient of the donor liver would testify.

The recipient has written that his surgery went great after he spent a year on the transplant list.

Ferrante believes this new evidence could lead to a reversal of his conviction.

An assistant district attorney told the court that the evidence about the transplant was all available before the trial and is not a reason to remand the case.

The superior court panel will either rule on just the motion for a new evidence hearing, or decide whether or not to grant a new trial.

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(© Copyright 2017 CBS Broadcasting Inc. All Rights Reserved. The Associated Press contributed to this report.)