Has the rightful criminal ever gotten away with it (let go) due to lack of evidence?

Just like an innocent person is falsely serving time in prison, has a rightfully guilty person gotten away with it because of lack of evidence and no confession?

Are there still cases like that... unsolved and while the cops themselves feel they really have the right person in the interrogation room (the person is really guilty; is lying) but can't do anything because they find no evidence at all and they person obviously isn't going to confess. Then they can't do nothing but let him/her go and they literally got away with it.

Even worse; no evidence at all, no confession and the liar passes the polygraph test too.

Has the rightful criminal ever gotten away with it (let go) due to lack of evidence?
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