CORAL SPRINGS, Fla. – How safe and secure is your personal mail after you drop it in those blue mailboxes outside a post office?
One South Florida woman says it's not.
Local 10 News has learned scammers are going fishing in those boxes, pulling out your mail.
Tracy Cohen of Coral Springs mailed out 20 invitations to a surprise party for a friend. But, to her surprise, no one got them.
"I had a couple of friends who actually texted me that they thought they weren't invited to the party and were giving me a little grief," she said.
Cohen placed the cards in the collection box outside the Coral Springs post office on West Atlantic Boulevard.
"I didn't want to put them in my mailbox at home because I was concerned that, you know, there was not a lot of security in that mail box, so I specifically drove to the post office to drop them off," she said.
But it seems scammers got her invites.
When Cohen went back to the same post office a month later to mail something else, she noticed the drop boxes were gone.
Inside, a postal employee said they had been tampered with.
"We do have reports of it happening in … Miami-Dade and Broward County," U.S. postal inspector Blad Rojo said.
File: List of recent U.S. mail fraud convictions in South Florida
Rojo showed Local 10 the homemade contraptions used by the thief or thieves to steal your mail.
One of them is a weight, attached to rope, with duct tape facing out.
"They will drop it into the collection box with the goal of having the mail stick to the tape, and then they can pull it back out, and now they have your outgoing mail," Rojo said.
That's not all. Another scammer used a pillow case, some tape and hanger. The thief placed the homemade device at the mouth of the box.
"Customers couldn't see it," Rojo said. "They were dropping their mail, and of course, it would just go into the sack, and then he'd be able to pull it out."
Rojo said thieves are getting their hands on checks and personal information that could lead to identity theft.
"They are counterfeiting checks or washing checks and using them for financial gain," Rojo said.
So is it safe to put mail in a collection box?
"It is safe to put mail in a collection box, but like everything else, we have to make adjustments," Rojo said.
Rojo's advice is never to place mail in a collection box at night, after hours, on a holiday or weekend when it won't be picked up and will sit there. He said if someone sees something suspicious like someone hanging around a collection box or a car parked for a long time at a collection box, report it.
As for Cohen, she is now going to take the extra time to park and walk into the post office.
"I definitely won't use a collection box again," she said. "This was a valuable lesson to learn and, luckily, it was just a party invitation and not anything valuable like a check."
These crimes are investigated. Tampering and stealing U.S. mail is a federal crime.
Postal inspectors have made six arrests since 2013. Prison sentences range as high as eight years.