A Faustian Bargain is when someone sells their soul to the devil. I believe that serial killers and mass murderers could be part of a Faustian Bargain because they kill all these people which is a terrible sin. These killers might not get a personal visit from Mephistopheles or Satan himself, however they can still pray to Satan instead of God, but I don't think they have a soul. How can someone have a soul and do such terrible things. Psychologists say they are sociopaths or psychopaths but there is more to it. Some mass murderers might "sell" their soul to their leader or their country. For example, in Norway a man killed a lot of intelligent children, the youngest being 14, that weren't from Norway because he wanted to keep his country pure. Also the Nazis sold their souls to Hitler and did what he ordered them to do. The only thing we don't know is if Serial Killers go to Heaven or Hell but most people want to believe they go to Hell and God wouldn't forgive them for their sins. However jail could signify Hell and being free can signify Heaven.
This connects to Dr. Faustus because Faustus sells his soul to the devil because he wanted to study magic. Faustus was warned by Mephistopheles and the seven angels but he still listened to the evil angel and sold his soul. Faustus uses his new power but only tricks people, but he does slap the Pope which is a terrible sin. However the sins he committed weren't too extreme but he was damned to Hell because God didn't forgive him for his sins. When Faustus was shown his life in Heaven and Hell he didn't like how Hell looked so he wanted his soul to be mortal but it was too late. Anyone who makes a deal with the Devil shouldn't be forgiven because selling your soul to Satan is a sin itself.