Harris, 34, initially was arrested on a charge of murder in the Sept. 29 shooting death of Cornelius Rashad Ramey, 25, of Gautier. Ramey was found dead inside his truck, which was parked outside a friend's home on Clemson Circle in the College Park subdivision.
"I was the victim," Harris said Monday. "I was just acting in self defense. I don't know what the DA (District Attorney) has been told."
Harris pleaded not guilty Monday to capital murder and an unrelated charge of second-offense domestic violence, which upon conviction would become a felony domestic violence case.
Municipal Judge Jason Thornton set Harris' bond on the capital murder charge at $500,000.
Gautier police initially arrested Harris on a charge of murder, but they upgraded the charge to capital murder last week because they believe the murder occurred during the commission of a robbery. Capital murder carries a maximum sentence of death.
Thornton set an Oct. 29 preliminary hearing in the murder case, the same day set aside for Harris to go to trial on the domestic violence charge. The domestic violence charge stems from an Aug. 30 arrest in the city.
Shortly after the killing, Biloxi police arrested Harris on Interstate 10.
Witnesses had described the vehicle for police.
Family and friends who gathered to console Ramey's mother after the murder said he had straightened his life out, recently earned his GED and planned to go to college.