Prosecutors have asked the Arizona Supreme Court to call off an upcoming hearing scheduled by a lower-court judge to determine the mental fitness of a prisoner to be executed in what would be the state’s first use of the death penalty in nearly eight years.

Arizona Attorney General Mark Brnovich’s office told the state’s highest court in a filing Wednesday that the May 3 mental competency hearing scheduled in Pinal County for death-row prisoner Clarence Dixon is likely to delay his May 11 execution. Dixon was sentenced to death for his murder conviction in the 1977 killing of Arizona State University student Deana Bowdoin.

The prosecutors are seeking to throw out the lower court’s order that concluded defense lawyers had shown reasonable grounds for planning a hearing over whether Dixon is psychologically fit.

Dixon’s lawyers have said their client erroneously believes he will be executed because police at Northern Arizona University wrongfully arrested him in a previous case — a 1985 attack on a 21-year-old student. His attorneys concede he was in fact lawfully arrested then by Flagstaff police.