What exactly happened in this case?
How old were the boys who abused the girl?
The article says that they penetrated her. Were they old enough to penetrate her meaning sexual intercourse? Did they abuse her in some other way?
Overall the ages of the perpetrators will really determine what sort of legal punishment can ever happen.
It does not matter what they penetrated with her. Legally it is regarded as sexual assault or sodomy. Their ages are not any sort of defense because there is no way they did not know it was wrong. Remember they threatened her to make her come into the bathroom so they could assault her.