Firstly, fuck this person and everyone else involved.
Secondly, she was a supportive witness that likely helped to get other convictions. She might be the reason that any money is recovered.
Thirdly, if the sentence for a crime gets too high, murdering the people who can rat you out becomes the best strategy. Dead people don’t take the stand. It’s why certain awful crimes, like assaulting children, seem to have too light of a sentence.
Not sure why you’re being down voted, it’s a fair question, and I don’t have a specific study to link to.
I just have anecdotes from working with criminals, and game theory.
If something will add X% to your time in prison, but has a Y% chance of preventing you from being convicted in the first place, there are numbers where it makes sense to risk it.
Granted, it’s much more likely in a single-victim sex-crime scenario than a fraud case that leaves behind kilometer-long paper trails