Attorneys for 30-year-old Gary Dunn say they expect prosecutors to try to prove Dunn's mother told Arkansas State Police that Dunn is a liar.
A motion in Johnson County Circuit Court says Martha Dunn should not be allowed to provide such testimony in the absence of testimony to the good character of Dunn.
The 19-year-old Dirksmeyer was found beaten and slashed to death in her apartment in Russellville on Dec. 15, 2005.
Dunn's trial is to start April 12 in Clarksville.
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