Cortez Sims walks into Judge Barry Steeleman's courtroom at the start of his trial on Tuesday.

A 20-year-old man who previously identified the shooter in a 2015 College Hill Courts homicide refused to testify against the defendant at his trial Thursday.

Marcell Christopher told Criminal Court Judge Barry Steelman he would not get on the witness stand during the second full day of the Cortez Sims murder proceedings.

"I don't know his name," Christoper said as an officer led him into the courtroom. "I ain't testifying."

Christopher told authorities on three occasions that Sims, then 17, was the shooter who came into Bianca Horton's apartment at 733 Main St. on Jan. 7, 2015, and opened fire, killing one, injuring two, and paralyzing a toddler.

Christopher was sent back into holding, since he faces unrelated federal gun charges, while Steelman ushered jurors into a separate room so they would not be present for the discussion, thereby affecting their opinions on the case. Moments later a courthouse officer had to jostle the 20-year-old back into the room.

"Mr. Christopher, you are before the court by subpoena, which means you are ordered to come here and testify," Steelman said.


Christopher said his mother told him not to testify. "I don't know nothing."

Steelman said he could hold the 20-year-old in contempt of court for disobeying his order.

"I'm already sentenced anyways," Christopher replied. "I can't do this. Go and do what you got to do."

Steelman sent him back into custody without punishment and prosecutors ultimately played a recording of Christopher's testimony from a March 2015 transfer hearing that ensured Sims would be prosecuted as an adult.

Sims, now 19, faces life behind bars if he's convicted on his charges, including first-degree murder, attempted first-degree murder and employing a firearm during the commission of a dangerous felony.

Prosecutors believe he is an Athens Park Blood gang member who was embroiled in a yearlong feud in 2014 with a rival street gang. To that end, they played a phone call Sims made from Hamilton County Jail in May 2016, the same month another witness from the case, Bianca Horton, was found dead on the 2100 block of Elder Street with multiple gunshot wounds.

Sims and Cornelius Birdsong, leader of the rival Bounty Hunter Bloods, discussed how Christopher had disappeared after cooperating with authorities, a no-no in criminal-gang culture, prosecutors said.


"I don't even want [Christopher] in Chatt no more," Birdsong says in the phone call. "When a — — do something, you keep that to the streets. You don't tell white folks. They don't just investigate one thing, they investigate everything. That right there is going to be a domino effect."

Prosecutors said Birdsong promised Sims he would try to find Christopher and order him to stop talking. Sims' defense attorneys countered their client said he didn't pull the trigger in the phone call, that he didn't want anyone to threaten Christopher, and that Christopher was lying.

Sims and Christopher met in a juvenile detention facility in Knox County between November 2012 and December 2012 and occasionally saw each other in Chattanooga, according to testimony and records that prosecutors introduced as evidence. Christopher was associated with the Bounty Hunters, and his name came up in a retaliatory homicide six days earlier.

After Sims was let into the apartment on Jan. 7, 2015, Christopher testified in 2015 that Sims walked into the room where he and Horton were staying. Face partially covered by a hoodie, Sims said his tag name, "Baby Watts."

Then, he opened fire.

So far, defense attorneys have tried to poke holes in the prosecution's case by saying the police hadn't solved a number of shootings from the 2014 feud. They insinuated that other men who belonged to different Blood groups in the area may have been involved. Earlier Thursday, when prosecutors called two Tennessee Bureau of Investigation agents, the defense also noted no DNA evidence linked Sims to the College Hill Courts crime scene.

Prosecutors rested their case Thursday evening around 7. That means defense attorneys can begin introducing their own evidence in the case when the trial resumes today at 9 a.m.

Contact staff writer Zack Peterson at or 423-757-6347. Follow him on Twitter @zackpeterson918.