But any mother who allows young and vulnerable children into unsupervised contact with someone she KNOWS is a risk to them, yes, she is complicit in what might go on to happen to them
He couldn't exactly remove the children he didn't have the authority.
And in hindsight knowing what he knows now he probably would have informed the police and social services although it doesn't look like the social services were willing to do anything other than talk.
Killing someone is a very personal thing and the responsibility for that death is certainly the responsibility of the person doing the killing.
In this case the arguments and physical violence probably led to the killing of these poor children and it's sad that children get harmed by their parents every day.....but to actually name him as complicit in this way is terrible.