Inmates at a Vermont correctional unit's print shop managed to sneak an image of a pig into the state police crest that goes onto police cars.

One of the spots on the cow in the state crest has been changed to the shape of a pig, a derogatory term for police. Police said someone who works at the print shop changed the emblem from the officially sanctioned design.

A police employee noticed the prank Wednesday and reported it. Police said the 16-inch door decals would be removed as soon as it was practical.

We understand that a lot of people will find humor in this, said Stephanie Dasaro, a Vermont State Police representative. But the joke does come at the expense of the taxpayers, Dasaro added.

The source and timing of the change to the design is under investigation.