SIOUX FALLS, S.D. (AP) - A convicted killer scheduled to be executed within the next month has written a federal judge saying he no longer wants to be represented by the Arkansas attorneys who've been challenging the constitutionality of South Dakota's execution protocol.

Donald Moeller is set to die for the 1990 slaying of 9-year-old Becky O'Connell. He wrote Judge Lawrence Piersol from the state penitentiary on Tuesday.

Moeller wants the federal case bearing his name dismissed.

The attorneys say Moeller's incompetent and incapable of making voluntary and rational decisions. They want to press forward with arguments.

The case focuses on whether South Dakota's use of the lethal injection drug pentobarbital in a one-drug method would inflict cruel and unusual punishment.

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