“Mr. Mitchell was just 20 at the time of the crime with no history of violence, while his juvenile co-defendant, who was the primary aggressor and had previously murdered two people in an unrelated incident, received a sentence of life imprisonment,” …“Mr. Mitchell was just 20 at the time of the crime with no history of violence, while his juvenile co-defendant, who was the primary aggressor and had previously murdered two people in an unrelated incident, received a sentence of life imprisonment,” …