New York Police Department's myNYPD Twitter fail
23 April 2014 Last updated at 22:47 BST
Twitter can be a very tricky place, a lesson the New York Police Department has just learned the hard way.
The force asked followers to tweet a photo of themselves with officers and add the hashtag "myNYPD" as part of a social media campaign.
But the pictures posted were less than friendly.
Nick Bryant reports.