Sickening, I don't care how old these worthless scumbags were when they did this, at a minimum they should face 50 years. The best way to deal with vermin like this is public hanging in their own communities and leave the bodies to rot. This is a gang problem. Destroy them and everyone else will finally be safe. Unfortunately, where the 'love the criminal, feel their pain, let them away with it' mentality will prevent justice being done.
Their parents should also be severly punished for raising violent gang rapists as a warning to all other terrible parents who fail to teach their children basic morality and decency. Evil is rarely born, it is nearly always raised very badly.
There is no politically correct, cuddly way to deal with the power these gangs have in certain areas. It is reprehensible to leave those unfortunate enough to live in these infested shitholes at the mercy of these gangs.