Today will mark day four of the capital murder trial of 46-year-old Sean Vincent Gillis, the Baton Rouge man whom authorities say has confessed to killing eight south Louisiana women between 1994 and 2004. He's on trial for the 2004 strangulation death of 43-year-old Donna Bennett Johnson whose mutilated body was found in a drainage ditch near the LSU campus. Wednesday, jurors reviewed three letters that Gillis allegedly wrote to a fellow prisoner describing himself as "pure evil" the night he killed Johnston using a nylon zip tie. Gillis pled guilty last year to second-degree murder in the 1999 slaying of Joyce Williams of Baton Rouge. He was sentenced to life in prison. The state is seeking the death penalty for the Johnston murder.