A prosecutor announced Thursday that no criminal charges will be brought in the case of an unarmed black man killed while being restrained by mall security guards.

McKenzie Cochran, 25, died at the Northland Mall in the Detroit suburb of Southfield in January. A day after he had been asked to leave the building over suspicious behavior, Cochran returned and reportedly told a worker at a mall jewelry store that he wanted to kill someone. The worker called security, and when Cochran wouldn't leave, guards pepper-sprayed and restrained him. He struggled on the ground as three officers held him for several minutes, one with a knee in his back.

Cell phone video shows Cochran crying out and saying, "I can't breathe," as shown in footage above from local outlet WJBK. He also asked for bystanders to call 911 and said he was dying.

"Stop resisting," a guard repeated several times during the incident, captured in a longer cell phone video from a bystander:

The Oakland County Medical Examiner's Office ruled Cochran's death an accident in March, naming the cause of death as position compression asphyxia.

"This is not an issue of whether these security guards were negligent," Cooper said, according to the Detroit News. "It's whether they were criminally negligent."

Cooper told reporters that the guards weren't trained to restrain Cochran properly. Security called local police but, in part because dispatch misidentified their location in the mall, it took 10 minutes for officers to arrive on the scene.

Cochran's family's attorney Gerald Thurswell told The Huffington Post that security also failed to tell the police that they were dealing with someone who had threatened to kill, which could have prompted a more urgent response.

Thurswell has filed a wrongful death lawsuit on behalf of Cochran's family against the mall, the individual guards and the security company, IPC International. But he told HuffPost that for Cochran's mother, it's not a substitute for criminal charges.

"The family was devastated," Thurswell said. "Her son's life was taken, a 25-year-old who didn't do anything wrong at all, and the people who killed him are not being held accountable through the criminal justice system."

Ron Scott, spokesman for the Detroit Coalition Against Police Brutality, addressed Cochran's death on Thursday.

"I don't know what an accident is, when you've got the knee in the back, compresses the chest cavity, which most police departments do not do, and security do not do, and then you say, 'He caused his own death by resisting,'" Scott told My Fox Detroit.