I'm Lucy, and I'd be happy to answer your questions today. I'm sorry to hear that this happened.
If someone else cashed a check made out to your tenant, that's fraud. Your bank should file a fraudulent endorsement claim and investigate. That's the whole reason people make out checks in the first place - to make sure the money goes to the right person. Call them again and ask to speak to a supervisor. But it's illegal to cash a check that is made out to someone else. You also have the ability to file a police report for theft by calling the police non-emergency number or visiting the police station. Since there's no immediate threat here, it's not necessary to call 9-1-1.
It's also a crime to open mail addressed to someone else, and you can report mail theft to the Postal Inspector.
The person who endorsed and cashed the check can also be sued for conversion, which is the civil equivalent of theft. They had no right cash that check, and should've either returned it (which is the right thing to do) or ignored it. That means you can file a lawsuit against the person who cashed the check for $4,000, plus punitive damages. These cases can usually be brought in Small Claims Court.
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