Your post is rendered nonsensical by the fact that children have been taken from homes or interfered by strangers while their guardians or parents were under the same roof. . What special conditions existed in 5a to make this an impossiblity?
It isn't nonsensical. It is just downright illogical and unkind.
There is a slither of British parents who think that they are perfect. Although God knows why. I certainly wasn't. I can only wonder what damage they inflicted on their children in the process of protecting them.
It certainly isn't possible to protect all of Earth's Children against deviants, of which Brueckner was undoubtedly one.
But I find it very hard to believe that Brueckner would have gone to such risky lengths to steal a child just to kill her.
It doesn't make sense when he could have snatched a child from the streets.
There is much more to this than we are ever likely to know.
In fact Brueckner could be the scapegoat who did the dirty work for others.