My only exp. w/native americans was bad they were liars and thieves, spouse is native am.;how to not be biased

I mean before knowing any personally I was a great fan/admirer of the native american people, but the ones I have had dealings with really are awful people. I know all are different, but these less than 1/2 breeds stole, neglected and lied to a person with mental disabilities; would love to hear from a native I would be proud and honored to know, get to know, I am in SW virginia...