A witness told a Criminal Court jury on Thursday morning she saw Stephen "Dollar Bill" Mobley gun down Gregory Watkins over a drug deal gone bad.
Constance Taylor admitted she had lied in previous statements to police, but said she was telling the truth now.
Mobley is facing a murder charge in the courtroom of Judge Barry Steelman.
Ms. Taylor said she had been a longtime cocaine user and she had begun buying from Watkins in April 2012. She said she later helped set up a drug exchange between Mobley and Watkins at her mother's house.
She said she has known Mobley all her life, saying his mother had married one of her uncles and his father married her aunt.
Ms. Taylor, who is now 31, said Mobley was not happy with the quality of the powder cocaine he got from Watkins. She said he did not make any threats, "but I could tell he was mad."
She said she arranged another meeting between the pair, but she said she did not know that Mobley was going to start shooting.
Ms. Taylor said Mobley picked her up at a male friend's house on Brainerd Road on the early morning of June 1, 2012. She said she had been in contact with Watkins, and they met at the Conoco on Brainerd Road.
She said Mobley's girlfriend was driving his white car, and she was a passenger along with Mobley.
She said he walked up to the Watkins vehicle and began firing. Police said the victim was shot nine times, and his female companion was also hit several times.
Ms. Taylor was charged in the case at one time, but she denied "making a deal" with the state.
Detective Lucas Fuller said a cellphone was found in the victim's lap. He said the latest calls were from Ms. Taylor. He said her name showed up on the call list in all caps.