Prove that the incidence of these are higher among immigrants than your citizens. Republicans in the US love to talk about illegal immigrants killing and raping people but then become suspiciously silent when Republicans and conservative donors are outed doing the same things.

I was not able to find any statistics on it. So your argument is inconclusive, unless you can dig up a statistic. However there has not been a single case of an assault gang rape done by ethnic Norwegians towards underage girls, in the same manner, at least not that has been reported by the police. (our newspapers are mostly centric/left-leaning, so it would end up in a newspaper if it happened)