A man suspected of shoplifting at an Ace Hardware Store has died after being tackled by two store employees and two witnesses.

On Thursday, Mischa Ryan Cox, 30, was tackled and detained by the employees and witnesses in the parking lot of the store at 612 E. 400 South. Police later put Cox in handcuffs, but one of the officers noticed Cox was not breathing and tried to revive him, Salt Lake City Police have said.

Police announced on Tuesday that Cox had died.

Cox showed no obvious signs of injury, and investigators did not know what caused him to stop breathing, police have said. Salt Lake City Police have said that the officers who found Cox at Ace Hardware did not use any force on him, but an outside agency — Unified Police Department — is investigating the death because Cox died while in police custody. The results of that investigation will be reviewed by Salt Lake County District Attorney Sim Gill.