HOUSTON --Houston police are investigating after a man was shot in the chest and killed after an argument on Houston's south side. Police say Johnnie Patterson and Courtney Aiken got into an argument when Patterson asked Aiken to leave his business at 6401 Cullen about 8pm on Monday. Aiken refused to leave and pulled out a handgun. Several witnesses then intervened and disarmed Aiken, who then fled the location. A short time later, Aiken returned and charged at Patterson. Patterson, fearing that Aiken had obtained another gun, discharged his own gun, striking Aiken one time. Aiken, 28, suffered a gunshot wound and was transported to Memorial Hermann Hospital where he was pronounced dead. Patterson, 56, was not injured in this incident. The investigation is continuing. The case will be referred to a Harris County grand jury.