I know how bad it feels getting scammed but killing them because of money is not wise and is inhumane. No money could afford a life of a person. A life sentence is what we can do most even if they deserve a more cruel punishment. Don't become a monster to them because of money.
Haven been victim of scam, i will recommend death penalty to ICOs, IEOs and STOs scammers because they have destroyed many homes and individuals, they deprived victims of freedom of expression after they might have carry out their dubious act of scam. Life sentence aren't not enough for them to feel the same as the victims.