In Knox County, Nicholas Sheley is charged with first-degree murder in the bludgeoning death of 65-year-old Ronald Randall of Galesburg.
Defense attorney John Hanlon contends the language used to determine who can be sentenced to death is vague and the Illinois Supreme Court hasn't clarified it.
Mike Atterbury of the Illinois Attorney General's office, however, asked Judge James Stewart to reject Hanlon's request that the death penalty be found unconstitutional in Sheley's case.
Sheley remains jailed in Knox County. He's also charged in five other killings last June in Illinois and with killing Tom and Jill Estes of Sherwood, Ark., in Festus, Mo.
The Galesburg case is being tried first. No trial date has been set.
(Copyright 2009 by The Associated Press. All Rights Reserved.)