RICHMOND, Va. -- Two United Nations human rights experts are calling on Virginia's governor to halt the execution of a man who killed two people in 2006.

William Morva is scheduled to be executed Thursday for killing a hospital security guard and sheriff's deputy after escaping from custody. Morva's attorneys say jurors weren't informed that his crimes were the result of a severe mental illness that prevents him from distinguishing between delusions and reality.

Friends and family members say Morva began sleeping in the woods, showed up barefoot at his father's funeral and was banned from a school campus after being found half naked on a bathroom floor. He showed signs of mental illness long before the killings took place.

Among those urging McAuliffe to stop Morva's execution are UN Special Rapporteurs Agnes Callamard and Dainius Puras. The human rights experts said in a statement Wednesday they are "deeply concerned" that Morva's trial "did not meet fair trial safeguards."

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Several state lawmakers are also asking McAuliffe to spare Morva's life.

CBS Roanoke affiliate WDBJ-TV reported the government of Hungary, where Morva was also a citizen, and the European Union are joining the final efforts to stop the execution.

"It's an extraordinary step on their part," Dawn Davison, a senior staff attorney from the Virginia Capital Representation Resource Center, told the station. "This is not something they ordinarily do. They met with him and asked that he grant clemency, and they also followed that up with a letter, which we're really encouraged by their interest in his case."