SIOUX FALLS, S.D. (AP) - An Arkansas-based public defender is asking a judge to appoint a guardian for convicted killer Donald Moeller, saying he's incompetent and incapable of making voluntary and rational decisions in a federal suit challenging South Dakota's capital punishment procedure.

Scott Braden filed the motion ahead of Thursday afternoon's court hearing. An affidavit from a University of California-Santa Cruz psychology professor says Moeller's abusive upbringing and deprived conditions of his confinement have undermined his will to live.

Judge Lawrence Piersol, faced with an attorney tug-of-war in the case, ruled Wednesday that Moeller must attend the hearing to determine whether he agrees with an attempt by Moeller's state court attorney to dismiss the case.

Moeller is to be executed in late October or early November in the 1990 killing of 9-year-old Becky O'Connell.