Torture never really prevented crime. It only made people become experts at commiting crime in secrecy.
Also, no human deserve to experience any of these torture regardless of what may. Some ancient rulers were worse than wild animals.
The reason Naira Marley and samlary is walking freely is because Nigeria is deeply corrupt. If this had happened in US or UK the inquest into mohbad murder will have been completed in his killers prosecuted. No justice in Nigeria. Worse of it are those listening to his music. Sad