TMZ spoke with multiple people inside the "Mug and Mallet" bar in Ocean City who confirm that cops entered on Saturday night looking for an underage drinker with a bowl haircut and a tiny frame.
But the only person who fit that description was a 27-year-old woman named Katie.
Katie tells us she had to whip out ... her ID and prove she wasn't JB -- though she says she gets mistaken for the singer, "all the time!"
If only the cops would've checked the real Bieber's Twitter page -- they would have known he was in The Bahamas with Kim Kardashian.
