White Flag Mystery: See How Close Brooklyn Bridge Is to NYC's Nerve Center

— -- The mysterious changing of the flags atop New York City's Brooklyn Bridge may have been a prank or a political statement, but the bridge's proximity to New York's most vital buildings made it a security breach that could have had serious ramifications.

The bridge is located just a few blocks from New York Police Headquarters, City Hall, and the New York Stock Exchange. A more nefarious intruder could have had access to New York's central nerve center.

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The city awoke Tuesday morning to find that the American flag on each tower of the bridge had been replaced with bleached ones. Police still don't know who swapped the flags, how or why.

According to police, surveillance video and evidence suggested that a group of people walked on the bridge shortly after 3 a.m., scaled the towers, covered the lights that illuminate the flags and made the switch.

Police admitted they don’t know who committed the security breach or how they accomplished it.

“I’m not particularly happy about the event,” NYPD Commissioner Bill Bratton said Tuesday.

NYPD Deputy Commissioner John Miller, who also oversees intelligence and counter terrorism, said tests were being conducted on the two flags.

"At this time, there is no sign of any particular nexus to terrorism or even politics," Miller said. "It could be someone's art project or a statement, but it's not clear what that statement is."