Do your solution is to allow more murderers of young girls in?
Personally I don't support policies that allow that.
Neither do I. How do you suggest they should have vetted this guy? By criminal record? Oh, he didn't have one. By mental health screening? Oh, he was clean. Well, there you go.
Did they "screen" Bernardo? Did someone magically fathom that he was a rape-killer and put him in jail before he killed anyone? No. Because it's impossible to figure someone's a rape-killer without a criminal record or mental health aberrant results.
So your brilliant solution is that you bar all single male Muslims??!!