Transcript for Authorities in London launch a full terror investigation of Parliament attack

Stay safe. Authorities have launched a full terror investigation especially because the attacker used a vehicle to kill. A terror method we have seen before, and heightened security in the United States as well. Heavily armed police standing outside the British kons late in New York, but they have collected key information. ABC's senior justice correspondent, Pierre Thomas, on the story. Reporter: Tonight British authorities are close to identifying this man, suspected of the deadly attack in London seen here, just after the fatal takedown. Sources say they have a name but they are still working to confirm the identity. We currently believe there was only one attacker. Reporter: Investigators are now urgently scouring the car he used in the attack and are searching for the suspect's smartphones and computers. In recent weeks, British counter intelligence officials have publicly warned about a possible attack using a car and a knife. Precise the crude type of attack ISIS has been calling on followers worldwide to carry out using any means necessary. This type of attack does not require anybody to go to any training. All you have to do is drive a vehicle and be able to hold a knife. Reporter: Last summer in nice, France, a huge truck plowed through a crowd. Killing 86 people. During Christmas season in Berlin, 12 dead and nearly 50 injured killed in another truck attack. That tactic used in the U.S. Too at Ohio state university when a student rammed into a crowd with his car then stabbed multiple people. And Pierre joins us live now outside of FBI headquarters. Pierre, we now know here in the U.S., some airports vigilance. Reporter: They are stepping up at landmarks, but they have no intelligence pointing to a plot at home, but they are worry about copycats and they are urging vigilance. Pierre, thank you. At the same time, that London attack was playing out, a

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