Anybody can sue anybody else for anything, the question is, will you prevail? Don't know. When people die, if they give gifts of their property, it is going to be contained as a directive in their will. It is also possible that he gave her these paintings before he died. You say it isn't true - but the real question is can you prove that isn't true?
Title &, Ch. 60 is called "replevin". Replevin is Norman French for "That stuff is mine and I want it back". It may require you to post a bond, depending on what the judge thinks. Replevin allows you to ask for the value of the property if it cannot be returned to you, or the property itself, and your reasonable attorney fees and costs of suit.
If there was a police report made at the time of the theft, that would be a good place to start. You can access police reports with a Freedom Of Information Act (FOIA) request. See what is there.
Also you can consider whether it would be smart - or not - to alert persons who might want to purchase the art that the ownership is disputed.
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