Parker and a friend, Jevontai Ingram, then 14, went into the Reliable Discount Pharmacy in south Oklahoma City near closing time May 19, 2009, at the urging of two men. They had been told to ask for the prescription drug OxyContin.
The men gave Ingram a gun, according to testimony in the criminal case. Parker was unarmed.
The pharmacist shot Parker in the head as the boy pulled on a mask inside the store, according to surveillance recordings. He then chased Ingram outside. He next came back inside the store, got a second gun and shot Parker five more times.
Ersland admitted to the shooting but gave conflicting accounts of what happened.
Prosecutors at his trial contended he went too far when he shot Parker again because the unarmed robber by then was unconscious from the head wound and not moving on the floor.
Ersland's attorneys said he was a hero who defended two female co-workers and himself.