These girls are indeed sick in the head and should be put away in an asylum for the rest of their lives, I mean no one in their right mind would commit a crime like this to summon the Slender Man. Which I will add in, does not work like that. According to the story Slender Man stalks his victim and the victim alone and when the time comes, he takes them to purgatory where he stalks/hunts them for all eternity, kinda like the boogie man. Also the Proxies of Slendy are nothing more than his eyes and ears, they do not kill and neither does the Slender Man.
Mortamor: Should these girls be found guilty they'll receive a prison sentence of 60-65 years so they'll be old ladies before they get out of prison if they are even still ALIVE by then. They ARE being tried as adults because of the severity of the crime. I also feel the need to add, WHERE THE HELL were the PARENTS and WHY was the one child's father so damned apathetic about this issue!? Some of the blame should be put on the parents too for doing such a crappy job of parenting.