A confessed child killer who asked to be put to death shouldn't be executed because he may be incompetent, defense attorneys argued Monday in a motion before the Kentucky Supreme Court.

Marco Allen Chapman's execution was scheduled for Nov. 21 after the Kentucky Supreme Court upheld his sentence last week. Chapman, 36, would be the first inmate put to death in the state in nearly 10 years.

The defense attorneys filed two motions with the Supreme Court on Monday asking for a stay of execution, even though Chapman dismissed them in 2004 before pleading guilty and asking to be put to death.

The public defenders questioned Chapman's competency in one motion for a stay. In another, they argued that Chapman shouldn't be executed until appeals are exhausted in a separate case that questions the validity of Kentucky's execution protocol. That case is pending before the state Supreme Court.

Public defenders Donna Boyce, Randall Wheeler and Emily Rhorer wrote in one of the motions that Chapman "will suffer the most irreparable injury known to law" if the stay isn't granted. "He will be executed before it is determined whether his execution would be legal," they wrote.