In 2010, when the murder took place, Rushing was already serving a 28-year prison sentence for killing his stepfather, who he believed had raped a young relative of his. (No evidence of the rape ever surfaced.)
At the Arizona State Prison Complex-Lewis, Rushing was forced to share a small isolation cell with Shannon Palmer, who had a history of mental illness and had been diagnosed with paranoid schizophrenia.
Palmer had been charged with criminal damage after he climbed a Salt River Project power pole during a thunderstorm and had to be talked down. He was reaching the end of his three-year sentence when Rushing killed him.
The cell was supposed to house one person, not two, and Palmer's erratic behavior aggravated Rushing, as Phoenix New Times detailed in a 2011 cover story.
Eventually, he snapped.
The brutal beating raised questions about the Arizona Department of Corrections' policies for housing inmates, as well as the lack of mental health services available to people like Shannon Palmer who wind up incarcerated because the state doesn't know what else to do with them.
In fact, after the murder, Rushing told Phoenix New Times writer Paul Rubin, "It makes no sense at all to put a murderer in a cell living assholes-to-elbows with a guy who is crazy and probably shouldn't be in prison at all. Bad things can happen in a house like that."
He explained, "Day after day and night after night of his paranoid bullshit, and his disrespect for women and children. It was almost pitch-black in there because they couldn't fix the lights. I couldn't read or think straight. This is what can happen."
During the trial, attorneys presented evidence that Palmer had still been alive when Rushing severed his penis with a shank that he'd fashioned from the blade of a disposable razor. He'd also wrapped a book in a bedsheet and used it to bash Palmer in the head, then gouged Palmer's throat open with the shank.
A Maricopa County jury sentenced Rushing to death in 2015. Shortly afterwards, he filed an appeal, arguing that his constitutional rights had been violated during the trial.
On Monday, the Arizona Supreme Court rejected the majority of his claims, but agreed with him on one point: The trial court had messed up by failing to tell jurors that Rushing was ineligible for parole.
The court's newly released opinion states that jurors were given "a 'false choice' of death, natural life, or life with the possibility of release." In fact, there was no chance of Rushing ever being released, since he was already serving a life sentence for murdering his stepfather.
That could potentially have influenced jurors' decision to impose the death penalty, the opinion notes:
The prosecutor implied that Rushing could be released by telling jurors in the penalty phase opening statement that the court had rejected the State's request for a natural life sentence for the stepfather's murder and instead imposed a sentence of life with the possibility of release after twenty-five years. Rushing had served fourteen years of his life sentence at the time of trial, and he was then thirty-five years old. Some jurors might have believed that if the court again refused to impose a natural life sentence, Rushing could be released after serving twenty-five years of a second life sentence, whether that sentence was concurrent with or consecutive to the first sentence. The jury deliberated for most of a day, and it is not possible to know whether even the remote prospect of release affected any juror's decision to impose the death penalty.
As a result of the error, Rushing's death sentence has been overturned — at least for now.
In its decision, the Arizona Supreme Court also upheld his conviction for premeditated, first-degree murder. That means it's now up to the Maricopa County Superior Court to hold a new penalty phase proceeding to determine the sentence that he'll face.