She'd rather her daughter had been murdered some other way? Being stabbed, for example? Would her daughter have been less dead if she'd been stabbed?
This is too stupid for words. The girl would have been killed no matter what the thugs had been using - they got mad, wanted to look big, and killed her, and they would have done so had they had to use their fists.
Mother is not listening. This has to do with the morality of the killers, not with their weapon.