A screen shot from twitter from the myNYPD hastag.
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New York Police Department's myNYPD Twitter fail

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.

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