Or, "defriend" her?

What if you kind of got along okay from a distance but she has a tendency to invade your privacy (open your mail, snoop, cross boundaries, etc.), and lie about you?

My problem: If I remove her as a "friend" distant relatives might ask about it. Then there's the likelihood of a no-win situation: If I tell them why I took her off, then that starts a family fight, gossip, etc. If I don't say why I took her off, then they hear her side of the story which, based on the history, is likely to be very offensive and pretty much a complete lie. Relatives are likely to believe her lies because she's been at an advantage for so long. As my mother, I was NOT "allowed" to correct her when she lied about me or I would get punished.

What would you do?