Yikes
Just read the Wikipedia entry for FGM.
Horror story, and in no way comparable (apart from the curious adherence to religious/social convention) to male circumcision.
AOG - what could the police do? By its very nature, these practices are carried out in secret - its not like these girls get thrown a FGM party, like a bar mitzvah. Therefore, with little information to go on, we should be wary of criticising the police for a lack of convictions.
Also, before anyone says, Well, they're afraid of upsetting ethnic minorities", I would like to point out that had that been true, FGM wouldn't have been made illegal in the first place.