Prosecutors say Neuman had a premeditated plan to kill Sneiderman and was having an affair with Sneiderman’s wife, Andrea.
Neuman was convicted of malice murder and possession of a firearm during the commission of a felony, according to a statement released by the District Attorney's office.
Neuman claimed he was not guilty by reason of insanity. A jury in 2012 found Neuman guilty but mentally ill.
In Neuman's second trial, a psychologist hired by Neuman's defense told jurors that she does not believe state mental health experts spent enough time with Neuman to properly diagnose him.
“You will come to the right verdict and that is that Hemy Neuman is not guilty by reason of insanity,” Delan told jurors in court.
Prosecutors argue that Neuman is not delusional but simply a “selfish” murderer.
“He wanted something that someone else had,” Robert James, Dekalb County district attorney, said in court. “He was going to do whatever it took to get it, including that, committing murder.”
“Ms. Sneiderman had nothing to do with the murder of her husband,” Sneiderman’s attorney, J. Tom Morgan, told ABC News in a statement. “Mr. Neuman acted alone when he killed Rusty Sneiderman and he should be found guilty of murder and punished for his crime.”
The District Attorney’s Office and Neuman’s defense attorney both declined to comment to ABC News prior to the jury's verdict.