AUBURN, Ala. —  The suspect in the slaying of an Auburn University student was indicted Wednesday on charges of capital murder and his attorney has filed documents to prepare an insanity defense.

Courtney Lockhart, 23, was also indicted on a charge of robbing a business in his Smiths Station hometown, District Attorney Nick Abbett said.

Lauren Burk, an 18-year-old freshman from Marietta, Ga., died March 4 after she was found lying on Alabama Highway 147 suffering from a gunshot wound. Her car was later found burning in a parking lot on campus.

Lockhart was arrested in Phenix City three days later after leading police on a short car and foot chase.

Authorities said he told police he abducted Burk from the Auburn campus, then robbed her and forced her to remove her clothes before shooting her.

He said he then drove her car back to the campus and set it on fire, according to investigators.

Lockhart's attorney, Joel Collins, did not immediately return a call seeking comment. But he is preparing an insanity defense, filing court papers claiming Lockhart has a mental disease and "lacks the ability to understand the difference between right and wrong."

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.