Eric Michael Thomas entered the plea Monday and was sentenced to life in prison. He was one of three people indicted in the murder of Stanley Neil Lyles.
Jonathan Richard Davis was also accused of capital murder in the Lyles killing. He pleaded guilty in March and also received a life sentence.
Officers discovered Lyles' body on August 23, 2002 in his home in Lauderdale County. He had been stabbed to death days earlier and his Ford Explorer was missing.
At the time of their indictments for capital murder, Davis, then age 18, was a Marine at Naval Air Station Meridian, while Thomas, then age 20, was a resident of Meridian.
An enlisted woman, Rosemary Rae Para, 20, was indicted as an accessory after the fact of capital murder. Para pleaded guilty to the accessory charge in November and received a five-year suspended sentence.