This is obviously a terrible thing to happen to an individual and i hope that the school and police can help the OP.

However, i think in general China is a pretty safe destination when compared to other options around the world. I've worked in Africa & Russia and experienced some pretty scary and intimidating situations but i still feel safer walking down a street in China than i do in the UK.

The one problem i have (and probably many others have as well) suffered from is bike theft. I've even had crappy third hand rust covered pieces of junk stolen. It seems if it has two wheels and is peddle powered it becomes irresitible to any passing thief.