Marty Is a Correctional Officer at a Federal Prison

Marty is a correctional officer at a federal prison. As a tool of intimidation, the inmates have formed a gang and continuously made threats to the officers and their families. Marty has never complied with the gangs' demands, which has caused great animosity between him and the gang members. One day, Maxwell, the leader of prison's gang, is to be released. Maxwell has told Marty that when he gets out, he is going to take his revenge on Marty by killing Marty's entire family. On the date of his release, Marty followed Maxwell to a liquor store. As Maxwell left the store, Marty followed him to a remote alley where Marty shot Maxwell six times in the back and neck. Marty's defense was that he stopped Maxwell before Maxwell could hurt Marty's family. Marty claims his action was in self-defense. Under what circumstances does the court recognize an individual's right to act in defense against another? According to the general rules of self-defense, is Marty justified in killing Maxwell? Why or why not?