As a general rule, knowing that something is illegal isn't part of the required mental state, even for acts that require doing something "knowingly"; that usually refers to knowing the specific facts that make the act illegal, not knowing the law under which those acts are illegal.

I did not say "simple" negligence, that is determined by others who know the specifics of this case.

Criminal law makes a distinction between gross negligence (locking the doors to a busy club so people can't get out which then catches on fire and kills everyone), and ordinary negligence (securing a heavy thing in the air with just a knot that falls and kills someone). Even if someone "should have known," that is almost never enough for criminal liability.

Thanks I know, I said that I don't know the specifics and that others (lawyers) will have to decide on that.