Two very different kinds of claim
One kind of case is about the owner's consent. A deed that was forged, or signed by someone who was deceived or pressured into it, can sometimes be set aside, though New York treats a forged deed and a deed obtained by trickery differently, especially once the property has been sold again to someone else. The other kind of case is about creditors. When someone who owes money transfers property for little or nothing, or in order to keep it out of reach, a creditor may ask a court to undo the transfer under New York's voidable transactions law. The facts that matter in each are different, and so are the people who can bring the claim. Sorting out which one you face comes first.
Building the record
Start with the recorded deed and the documents filed with it, which in New York City are available through the city's online land records and elsewhere through the county clerk. Look at who signed, who notarized, when the deed was recorded, and what price or consideration was stated. For an owner who was deceived or whose signature was forged, medical records, accounts from people present at the signing, and communications with the person who received the property often matter. For a creditor, the timing of the transfer compared with the debt and the relationship between the parties tend to be central. Report suspected deed theft to the police or the district attorney without waiting, since several New York prosecutors' offices and the attorney general have made it a focus.
Protecting the property while the case runs
A challenge to a deed is usually brought in state Supreme Court, and the claimant can often file a notice of pendency so that anyone checking title sees the dispute. That step matters because the person holding the deed may try to sell or borrow against the property while the case is pending. Courts can also be asked for orders that keep the property in place in the meantime. In a first meeting we review the chain of recorded documents, decide which theory fits your facts, and discuss who should be named. We also look at whether a title insurance claim, a probate proceeding, or a criminal case is moving in parallel and how that affects timing.