We have a joint tenancy deed. When my husband passed away, I found out that 6 yrs. Ago he filed a beneficiary deed to someone without my knowledge. I never signed it. This person now claims it is her land. I disagree. We live in AZ with right to suvivorship.

When he gave this other person a deed, it destroyed the JTWROS. He, in effect, conveyed his 1/2 undivided interest in the property to her. So now you each own a 1/2 undivided interest. Either or both of you have the right to occupy the property.

See a real estate attorney about suing her to "partition" the property. Usually, it would be sold and each of you get 1/2 of the proceeds.