A Salt Lake City pediatrician who was convicted of killing his cancer researcher ex-wife and is set to be sentenced Wednesday still maintains his innocence.

In a letter sent recently to the judge, John Brickman Wall, 51, said people around him misinterpreted his confused state as guilt when he was actually dealing with grief and psychological trauma from police interrogation.

"If the available physical evidence is examined with the logical and intellectually honest approach of a scientist, I am exonerated," Wall wrote in an eight-page letter picking apart the evidence prosecutors used at trial. "I am innocent, before my God."

A jury found Wall guilty of murder earlier this year in the 2011 death of his wife, Uta von Schwedler. Her death initially was ruled a suicide, but he was charged with murder more than a year later after her friends and family pushed investigators to look at Wall as a suspect.

Prosecutors said Wall attacked the 49-year-old von Schwedler with a knife, gave her the anti-anxiety drug Xanax and drowned her in her bathtub. Wall's attorneys said it was more likely von Schwedler killed herself.

His oldest son, Pelle Wall, became convinced his father killed his mother, based partly on his dad's bizarre behavior and comments after von Schwedler's death. That included John Wall asking his children shortly after their mother's death if he was a monster and responsible for her death, his daughter testified during trial.

After his father was found guilty in March, Pelle Wall called the verdict an end to a 3½-year quest for justice.

In the lead-up to sentencing, John Wall, his parents and siblings have sent letters to state Judge James Blanch seeking a lighter sentence.

Wall's sister, Wendy Wall, who has defended her brother all along, said in a letter to Blanch that the man depicted during the trial bears little resemblance to the brother she knows. She said he was a loving, doting father who wasn't violent.

"Johnny is one of the most decent, compassionate and self-sacrificing people I have ever known," Wendy Wall wrote.

His brother, Michael Wall, asked the judge to take into account that Wall already has suffered immeasurably by being separated from his four children.

"Johnny could suffer no greater torture than his physical, and now emotional, isolation from his children," Michael Wall wrote.

John Wall said in his letter that he was a non-violent man raised in a pacific, Mennonite tradition. He said he loved von Schwedler dearly before their relationship soured and is distraught over losing custody of their four children.

He wrote that sending him to prison won't bring von Schwedler back, but it destroys the lives of the living members of the family.