TRIGGER WARNING; Should people be held responsible for not testifying?

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So I’m working on season 10 of SVU and there is an episode about a rape and the victim refuses to testify. She is told that by testifying and helping put her abuser in jail, she could save countless other women from also being attacked. If she doesn’t, more women might be raped.

I haven’t finished the episode so I don’t know how it pans out, but my question is, do you think people who WITNESS and/or are the VICTIM of a crime, but refuse to testify, should be held legally accountable if the perpetrator strikes again? What about morally/ethically responsible?