NEW YORK (CBSNewYork/AP) - - Two young artists from Germany have claimed responsibility for the flag swap at the Brooklyn Bridge.
One of the two was spotted on security video at a subway stop near the bridge in the hours before the switch was made, sources told 1010 WINS' Juliet Papa.
Sources also said others were involved, some from the New York area.
Mischa Leinkauf and Mattias Wermke say they hoisted the hand-sewn white flags onto the 131-year-old bridge's towers as a celebration of public art in "the global center of creativity.''
Source: German Artist Seen At Surveillance Video Near Brooklyn Bridge
The NYPD is looking into their claims. But a law enforcement source told WCBS 880 they are believed to be credible.
The source said there is evidence linking Leinkauf and Wermke to the incident, WCBS 880's Peter Haskell reported.
PHOTOS: Mysterious Brooklyn Bridge Flags
De Blasio said he's leaving the case to law enforcement, but that the incident "looked like trespassing" to him, among other charges.
"If they have violated a law, of course they should be prosecuted," the mayor said.
According to sources, the pair could be charged with burglary -- a felony -- and other charges, including trespassing, Papa reported.
NYPD Investigating Claims By German Artists
As CBS 2's Tony Aiello reported, not everyone thinks the pair should be charged.
"I like that about New York. I like that unexpected things happen," Kristian Roebling said.
Roebling is one of millions who love the Brooklyn Bridge. It's in his DNA. His great-great-grandparents Washington and Emily Roebling supervised the building of the bridge which was designed by Washington's father John John August Roebling.
Leinkauf and Wermke said that they switched the flags early on July 22 to commemorate the 145th anniversary of German-born Brooklyn Bridge architect John August Roebling's death.
"I think it is a beautiful and poetic resolution to something that could have been much more nefarious, and it wound up being a pretty artistic gesture," Roebling said.
In a statement, the artists said they "were careful to treat the bridge and the flags with respect,'' but they didn't address potential criminal liability from the project.
They said they followed U.S. Flag Code in their handling of the American flags they removed and were returning them, but they have not said how or when.
The day the flags went up, NYPD Deputy Commissioner John Miller, the department's counterterrorism and intelligence chief, said he believed four or five people scaled to the top of the bridge's towers and swapped the flags in the dead of night.
Miller said the people involved appeared to use aluminum cooking sheets to cover the lamps illuminating the American flags that usually fly there before hoisting the white replacements.
Video footage of the security breach shows the people walking on the bridge's footpath at about 3:10 a.m., and the light on the bridge's Brooklyn tower flickers and goes dark about 20 minutes later, Miller said.
The same thing happens about 12 minutes later on the Manhattan tower, he said.
It's not the first time someone has claimed responsibility for the flag incident. Previously, the "New Pot Party" claimed responsibility for the flag swap. A parody Twitter account also claimed responsibility for the incident.
NYPD Deputy Commissioner Stephen Davis said that if the artists have the flags, "we certainly would love to have them back.''
Leinkauf and Wermke have scaled buildings, bridges and statues in a series of projects blurring the line of access to public works and spaces. In 2007, according to their website, they tied balloons to cables high above the Brooklyn Bridge roadway.
The German artists first made their claim of responsibility to The New York Times.
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