WAUWATOSA, Wisc. (CBS Local) — A postal worker has admitted to stealing thousands of greeting cards filled with cash or checks after authorities caught her red-handed.

Residents in the Wisconsin city just outside Milwaukee complained to their local post office after they weren’t receiving expected graduation, birthday and wedding cards in the mail. The FBI stepped in to help figure out why.

Ebony Lavonne Smith, 20, was caught after law enforcement placed a transmitter in a test greeting card along with a $20 bill. The transmitter signaled to authorities after it had been opened. The card was designated for another route, but a USPS supervisor noticed Smith looking through trays from other routes and pulling out letters that appeared to be greeting cards. When Smith delivered the baited letter to its address, the transmitter activated and authorities waiting at the address approached the carrier.

Smith, of Milwaukee, was arrested and later admitted to stealing more than 6,000 cards with cash and checks. The postal worker pleaded guilty to theft or receipt of stolen mail last week, and told officials that she stole anywhere from $50-$100 per week.

This isn’t the first time something like this has happened in Wisconsin. Last November, a postal worker in Milwaukee allegedly tampered with mail and was accused of stealing money as well.

It still not known if the money stolen by Smith was returned to its intended recipients.