If your step-daughter is entitled to money from your late husband's estate (either by will, trust or laws of intestacy), then she can sue you. However, she will need to sue you in the state where his estate is being administered.
I wouldn't play around with this though. If you know she's entitled to something and you deliberately withhold it for your own benefit, you could be criminally liable. All she would have to do would be to report the taking to the local district attorney.
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