It is legal to claim unclaimed property if you are the designated owner or beneficiary. In order to do so, you will need to provide supporting documentation proving your identity and relationship to the former property owner. This can be somewhat challenging; although it is still legal to file as long as you have a legal claim to the property.

If you're question is whether it is legal to claim fraudulently claim someone else's money, the answer is no. If your question is whether it is potentially possible for someone to commit fraud, then yes. The person whose property it was should contact the unclaimed property administrator to review the transaction.