AUBURN, Ala. -- An attorney is preparing an insanity defense for a man accused in the slaying of Auburn University freshman Lauren Burk.

Defense attorney Joel Collins has filed court documents that describe Courtney Larrell Lockhart as "suffering from some mental disease," saying he "lacks the ability to understand the difference between right and wrong."

Lockhart, 23, of the Smiths community has been charged with capital murder in the March 4 death of the 18-year-old student from Marietta, Ga.

District Court Judge Russell Bush has ordered an evaluation of Lockhart by a state psychiatrist or psychologist before setting a trial date. He also issued a gag order covering parties in the case.