Tickets for "The Book of Mormon" on Broadway are selling like hotcakes, but some of them are fake.

The show's staff has come across five sets of counterfeit tickets in the last two weeks. All of the fake tickets were bought on Craigslist, picked up at different locations around the city, and are believed to have been forged by a single individual.

According to company manager Adam Miller, the first case came to light two weeks ago when a party of eight arrived with false tickets. “When the ticket takers scanned the tickets, they knew there was something going on,” said Miller.

For somebody who handles tickets all day, it's easy to tell a counterfeit ticket from a real one. “The colors are off, and the fonts are wrong. The back is sort of pixilated, and the weight and texture of the tickets are different,” he said.

Still, Miller said the tickets were relatively sophisticated and he could see how buyers were fooled—especially since the false tickets scanned the same way as a real ticket to a mezzanine seat would. That led the show’s producers to believe the counterfeits were produced by copying a legitimately purchased ticket.

Although counterfeit tickets on Broadway are rare, they are not unheard of for popular shows. In 10 years working on shows, Miller said he hadn't seen a case of people trying to enter the show with fake tickets yet—until now.

The New York Police Department is currently investigating the case.

Tickets to "The Book of Mormon," which start at $69, have been sold out since the show opened on March 24. The show set a house record at the Eugene O'Neill Theatre by bringing in $1,014,228 last week.

“We’re selling really well and getting a lot of attention, which is great,” said Miller. “But I think, unfortunately, someone has decided to take advantage of people who haven’t been able to get tickets.”

The show’s producers recommended buying tickets directly from the box office or from Telecharge to avoid getting scammed.