38-year-old Earnest Mosley, Jr., Monday admitted his guilt in Lauderdale County Circuit Court.
Mosley was sentenced to 20 years without parole for manslaughter.
Officials say Mosley shot Mason several times.
District Attorney Bilbo Mitchell says the guilty plea brought a sentence which likely matches what a jury trial would have brought.
Mitchell says Mosley's attorney would have argued self-defense.
"While it started as a self defense of him and of others, it ended up going too far," said Mitchell. "In the end, the guy did not have to die. He could've stopped shooting before he did."
Mitchell says Mosley will have to be on probation for 10 years after his release in 20 years. He said that means Mosley will be under state supervision until he's 68-years-old.