Capturing Manhattan terror attack suspect Sayfullo Saipov alive was an important step toward learning more about what he knows and if there are dangers of further attacks, New York Police Department Deputy Commissioner of Intelligence and Counterterrorism John Miller said Thursday.
"When you capture a live terrorist, you have the ability to question that person and you're able to glean a lot about those things, were they part of a larger network, is this something bigger, were they acting alone," Miller told "CBS This Morning."
Further, he said, investigators can dig deeper, to learn about what brought Saipov, an immigrant from Uzbekistan, to the point of renting a Home Depot truck and using it to run over people on a downtown bike trail on Halloween afternoon.
"There are former defendants in cases like this, where we've learned a lot about the arc of their radicalization," Miller said. "What we're seeing today is in the United States, a great deal of that is just done online."
The NYPD is working with the FBI to determine whether the attack was inspired by ISIS or if Saipov was communicating with ISIS over cryptic channels to direct a plan.
"At this point we don't see anything that leads us to believe anyone else is involved, but we're only two days into it," said Miller.
It also appears that Saipov was radicalized after arriving in the United States, said Miller, but "this could change."
Miller also commented that he does not know about President Donald Trump's statement that Saipov brought in others to the United States and that he'd been the point of contact for 23 people.
"I think he seems to be referring to other people that came in [through] that visa program," Miller said. "Part of that program is that once you get here, you have the opportunity to bring in family members."
A note was found in the rental truck used in the attack, and Miller said it has "a lot of potential significance."
"It says 'the Islamic State will endure forever' multiple times on a couple of pieces of paper, but the fact is the note was left on the scene, on the ground, means he was following the ISIS instructions," said Miller.
He explained that under ISIS directives, people carrying out attacks must give credit to the Islamist jihadists, such as by yelling out slogans, posting the action online or leaving leaflets.
Meanwhile, authorities have had difficulty figuring out how to stop such radicalization since the 9-11 attacks, Miller said.
"This is something we have been in discussion with the larger Muslim community about how to do, and we're not there yet," Miller said. "We have no effective counter-message today."
© 2022 Newsmax. All rights reserved.