'That dad in Crete being one, he threw his kids off a balcony while on holiday.'
That man was very, very insane, with a long history of psychiatric problems. How social workers and the courts found he was okay to have those children in his care unsupervised, I really don't know, because he was very ill.
This person appears to have abducted her children, to the point where she'd had her passport removed as she was a flight risk.
And sadly, not all who commit crimes like this are of unsound mind. Not by a long shot.
It really niggles me that when people do this, especially women, everyone concludes she must have been mentally ill.
That's not a given, and the idea that is it perpetuates the fear many who are mentally ill feel in seeking help because people make assumptions about the kinds of actions they are presumed capable of committing.