That's probably too harsh, unless it can be proved without doubt that exactly and only due to this X (many) children died and would (with high probability) live otherwise. Thats China level of dealing with similar situations, plus probably harvesting organs for additional profit afterwards and sending bullet receipt to the family.

There are many existing punishments - go after all their wealth, family and connected business, trusts etc. Simply ban them from western financial world. Publicly shame them and make their name a curse to spit on. Properly harsh jail and making sure all inmates know who arrived, I wouldn't expect kinder treatment than pedophiles get. And so on.