Last week, I was brushing my teeth before bed when my wife walked in with her iPhone in hand and a panicked look on her face. She’d logged into her Santander (SAN) banking app to check the balance on her checking account, and $7,800 had been mysteriously withdrawn.

A few days earlier, we’d sent in our first rent check for a new apartment — so we initially thought we’d somehow written the wrong amount on the check. Stranger things have happened, right? If that were the case, we could have just asked our landlord to mail us the amount we’d overpaid.

But that wasn’t the case.

A mailbox isn’t a safe

When we learned that our landlord didn’t even receive our rent check, let alone cash one for more than twice our rent, my wife reached out to her bank. They told her someone had cashed a check in her name for $7,800 in New Jersey. We live in New York.

The forgery was even more obvious once we saw the actual check. Someone had stolen the check we mailed, erased the amount and recipient — and wrote in their own amount and recipient.

Yes, in a time when most people worry about having their online accounts hacked, identities stolen and banking logins swiped, we were the victims of decidedly low-rent crooks.

That doesn’t mean it was easy to get the money back. You can’t just go to the bank and say you’ve been defrauded: We had to go to the police station to file a report before the bank would even start its own investigation.

And in a weird twist, my wife couldn’t file the report at the New York City Police Department precinct closest to her office. Instead, she had to go to station closest to where she discovered the crime. That meant going to the precinct near our apartment.

At the precinct, my wife explained to the detective assigned to our case every last detail about when and where we mailed the check. As it turns out, we weren’t the only ones in our area who had their rent checks stolen.

The police said criminals had been swiping mail from public mailboxes on a regular basis in one of two ways: Either they had the keys to the boxes, or they used a string with something sticky, say a glue trap for a rat, on the end to fish for envelopes.

It’s become such a problem that, according to the officer, the postal service has begun replacing the old mailboxes with large pull-down flaps for new ones with small envelope-sized slots. In fact, the mailbox we put our check in was actually one of the newer models. The detective wasn’t sure how the thieves managed to swipe our check from the new box, but he figured they likely stole a key.

A Santander representative issued a statement about fraud cases saying, “Like all banks, we are always on alert for attempts to fraudulently access our customers’ accounts, and our systems are designed to detect and prevent such activity. We urge customers to sign up for our fraud alerts and report any fraudulent activity on their accounts to us immediately.”