Transcript for Brooklyn Bridge Flag Swap Still Shrouded in Mystery
The mystery in New York City over the white flags that someone or group put up high on top of the Brooklyn Bridge. Now police want whoever did this to surrender themselves and they are very serious about the security breach look at these images side by side the American flag. Usually flies over the bridge and one of the flags it was replaced with for a few hours -- -- flag. In the middle of the night side by side -- I'm Michelle Franzen New York the bleached white American flags were removed that this investigation is far from over ABC's -- Gonzales watching this story in New York today. With more Marcy. Hi Michelle -- investigators don't think this was something sinister at this is a major landmark with lots of security measures in place. So the fact someone was able to get past them all the pull this off. It's raising some serious concerns. A mystery high above New York City. The two American flags that always fly atop the Brooklyn Bridge somehow switched Al yesterday morning -- -- a pair of old glory is apparently bleached white. I want the American flag there. I don't know why represented -- surrendering. Investigators say they don't know if it was meant as a -- an art project or some kind of political message of surrender -- they have ruled out terrorism the NYPD and city officials are concerned and determined to track down whoever's responsible. The only big club -- -- that should be surrendered at this time. -- -- -- All of the desecration of this way. Police now zeroing in on the moments they believe the flags were switched this earth canned video shows at 3:30 yesterday morning at the light illuminating one of the flags flickering -- Twelve minutes later the same thing with the other flag. Officers later finding the light had been covered by these aluminum pan secured with a zip ties. They say who ever did this was able to scale 276. Feet. Somehow making it past police who monitor the bridge 24/7. And through the locked gates atop the bridges steel cables. Perhaps some indication that they have experience climbing. In construction or in bridge work. Or that they may have actually been up there. For a breach police are not taking lightly. Now Marcy investigators say they don't know who is responsible but are they any any closer to -- -- now. -- showing other trying to track down for five people who were seen walking across the bridge about twenty minutes before that first light -- out another not necessarily saying. That those could be to people responsible they just want to talk to them and see if maybe they noticed anything and can point investigators in the right direction. And Marcy give us an idea how people are reacting to the security breach. I -- it's of course is raising a lot of concerns and making people ask. How safe are we really -- -- this again is a major landmark so many security measures in place there's. A police officer -- 24 hours today there are lots of security cameras so how did somebody get past this and what this event somebody who had some kind of malicious intention. I'm so definitely people here in New York are are pretty worried. Out -- -- they're also talking about it on line let's share this tweet a little bit at just a few of them that's burning up. The Internet here so -- US flag over the Brooklyn Bridge was replaced with a white flag and security never -- -- -- thing. And then there's this one also. People are freaking out because someone put a white flag. On top of the Brooklyn Bridge aren't -- more important things to be concerned about so Marcy give us an idea about. If there is a reward that police are offering at this point. We -- -- Brooklyn Borough president is offering a 5000 dollar reward for information leading to an arrest. Very good RC Gonzales thank you for joining us. And we want to turn -- you bring in ABC's crime and terrorism analyst Brad Garrett via Skype from Washington DC Brad thanks so much for joining us. I have to ask you what struck you when you heard about the success of this -- which -- give us an idea of the time effort. And implications that something like this could happen any post 9/11 world and -- New York City. One of the failings. Security many times are. No one monitoring the cameras. -- -- the situation at the Brooklyn Bridge with uniform officers -- -- and the group -- extensively covered by surveillance cameras but that doesn't do you much good if you don't watch them as you might recall. There's been a number of breaches at the new World Trade Center. There -- people have gotten to the top and spent. Literally hours at the top four they were caught. Again suggesting. Adequate security in place that you don't have somebody monitoring it it's not much good. As far as the ability to pull this off think about the Brooklyn Bridge you have the ability to both walk -- -- a -- Across the bridge so with normal foot traffic so much it clear clearly ride in perhaps with some knowledge scale up. Again it's no one's watching Cambridge may have allotted time to do this and apparently they did. They did -- some time -- not an easy job but what is the concern here. For NYPD security and what should the public take away that this iconic bridge security was breached. I think in -- TD is going to have to take it very hard look at probably the Brooklyn bridge and other locations. As far as how they -- monitoring those bridges and locations in other words yes we have cameras. Are there people regularly checking them now. Granted watching cameras can be extremely boring and you have to talk people out regularly to stay on top of it but that's really no excuse. It's going to be a combination. -- -- And can they reconfigure. Patrol officers to better cover any -- extent or another group that liked us to to -- a flight on top. My biggest concern with this is you know it doesn't look like somebody want to -- the bridge they wanted to make a statement whatever that might be. But he does the -- fuel fall for people who want to do bad things like him. But how easily they got up here maybe I could do something and I actually wanted -- -- -- -- -- harm people. That's exactly right at the BT is and -- -- said that it doesn't believe this flag incident is tied to terrorism. Are they saying how they were able to rule that out so quickly. And who might they be looking for students making a statement -- -- I would say the following that. They're gonna look at probably surveillance. Footage as to exactly what turned the lights actually -- -- -- were blocked out. -- if they have closer cameras analyze who might be there my senses though probably figure out going backwards. Could possibly did this. But. You know again that the real keys going to be how can they reconfigured. Their security. At the bridge and maybe at other locations. To at least catch seasonings as they -- want another words you can't stop people and shouldn't. Going across Brooklyn Bridge. Which you should be able to immediately intervene. If in fact they try to pull something -- like this. Or something far worse were they attempt to damage the bridge or harm others. ABC's crime and terrorism analyst Brad Garrett thank you for joining us. And you have been watching and keep up with that story -- real time by downloading the ABC news -- and starring this story for exclusive updates on the go. For now I'm Michelle Franzen in New York.
This transcript has been automatically generated and may not be 100% accurate.