Try them as adults.
Life without parole. Death penalty unfortunately not possible due to their ages.
Let them sit in their prison cells for the next sixty years and reflect upon what they did.
Hearing about this, all I can remember is my one of my dad’s (retired copper) last words to me: Anyone hurts any of the women in this house, take them out. Don’t count on the system to take care of it. I know you are smart enough to not get caught.