Would you call the cops?

[Aliantha]

Today at work, one of my co workers was telling me about something that happened to her Grand daughter yesterday.

GD was walking home from school past the school bus stop when one of the boys flopped his member out and started rubbing himself up against her - masturbating.

GD called out to her brother who was some distance in front with his ipod stuck in his ears, so he didn't hear her.

The other 'boys' at the bus stop were egging the masturbator on.

Somehow GD got away (I don't have any details on how) and went home and told her mother.

Mother called the school and the boy has been suspended and the 'boys' have all been reprimanded.

Grandmother says they weren't intending to call the cops because the school is dealing with it. Also, that the perpetrator has what sounds to me like aspergers (grandma says he has something wrong with him where he doesn't understand boundaries) so she feels sorry for him to an extent.

My view is that it was sexual assualt and this girl is likely to be traumatised for some period of time if not long term. Also, this boy has committed a crime and the other 'boys' are almost as guilty.

What do you think? Should I call the police and report what is in my opinion a crime even though I wasn't there and all the info I have is third hand?