Transcript for Authorities identify gunman in Las Vegas mass shooting

Pierre Thomas, thanks very much. People are wondering how they were able to, authorities were so quickly able to spot him and get into that room and ABC news contributor and former FBI agent Brad Garrett will talk to us about that. 4 1/2 minutes and it's an incredible -- how they were able to find them. Tell us how that went down, Brad. Well, the key, robin, in every mass shooting is what the witnesses immediately tell you. So you have a guy elevated on the 32nd floor. Were there people in rooms of proximity that heard it that maybe even saw the fire coming out of that particular balcony, for example? And you take that information and you immediately, you know, rally the police in particular the S.W.A.T. Team and it looks like to me that they got to that particular room fairly quickly, but keep in mind, virtually every mass shooting is less than five minutes, it looks like this one fits that profile. But this guy because he had multiple weapons, I'm going to guess, was able to get more rounds off than a single weapon that you would have to constantly reload and he also had cover, because he's in this hotel and he's up. He isn't like one of these school shooters or even OMAR Mateen who goes into the Orlando nightclub and is face-to-face with people that he's going to shoot, the police can get to that -- that sort of individual particularly potentially quicker. It seemed like authorities were confident they had the right room when they went in. It was very clear and that's why I think they had some really good eyewitness information that that's where the guy was and maybe thehad some pieces of this was, robin, about a guy that carried maybe too many bags in there to stay for one night. There may be other things that play into why they went in that room but clearly I think witnesses probably helped them. Thank goodness, all right, Brad, thank you. They got there so quickly but not before so many killed and

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