“Following the great season the Chicago Cubs just had, counterfeiters may see this time as a good opportunity to take advantage of the fans’ excitement and distribute questionable items to the public,” Special Agent Brian Brusokas, a member of the FBI’s Art Crimes team which investigates fraud regarding collectibles, said in a statement.

“These items can include everything from autographs to game-used items such as jerseys, bats, balls and caps. We can also see a flood of unlicensed t-shirts and other items commemorating this special year,” Brusokas said.

Before buying any limited-edition items such photos, card sets or display items, Brusokas said consumers should know the edition size because some limited-edition memorabilia is only limited by the amount of consumer interest.

Buyers of game-used items like jerseys should know what a genuine on-field Cubs jersey looks like, and pay close attention to details such as the stitching patterns used to affix nameplates and patches, according to the FBI.

For autographed baseballs, buyers should consider comparing the signature on the ball to known signatures of that player and, if the signature has been authenticated, consider the qualifications of the authenticator.

The FBI advises customers to know who they are buying from and what their refund policy is, and always be mindful that if an item seems too good to be true, it probably is.