I posted a link and a rant about how horrible this case was - but I do NOT blame the girls as such. I blame the collectivisation of the family and the prosecutorial steerage of it. Parents do not have enough authority to discipline their own children, and too much of the village is doing the raising.
But the proper course here would be 1) a total, stern rebuke from a public figure of both the police and the DA's office, with a profuse apology to the victim and a determination to review policy 2) a forced public apology from the girls themselves, before their schoolmates and with the victim physically present. The best punishment for a child is to make them feel honest, righteous shame for their behavior. To scare them this way was not only mean-spirited, it was useless - fear only makes for more fear, while shame makes for an adjusted personality. The direction of law enforcement and punishment is organized around fear, when it should be organized around shame. For example - the Japanese have one of the safest, crime-free societies known, because no self-respecting Japanese would subject himself to the crushing shame of bad behavior. Fear of punishment by the state does not work. Shame, the self-punishment of a healthy conscience, does. If kids were raised to feel healthy shame instead of "you're all just wonderful angels!", they'd grow up much better and be much more circumspect about what they do. Then the prisons could go back to being used to lock really bad people away.
As for the victim - he should sue the fucking shit out of everyone in sight in Garden Grove.