ROBERT SIEGEL, HOST:
With hindsight, there is several things about Ahmad Khan Rahami that might have been warning signs to authorities.
ARI SHAPIRO, HOST:
As we just heard, there were the bomb materials he purchased on eBay under a name very close to his own and had shipped to a place where he worked. And there was his year in Pakistan. A few months after Rahami returned in 2014, a family dispute led his father to tell police that he suspected his son was involved in terrorism.
SIEGEL: Well, the police kicked those concerns up to the FBI's Joint Terrorism Task Force in Newark. The bureau moved on, though, after a few weeks of inquiry returned no additional leads.
Here to tell us about the FBI's process in situations like this is Jeff Ringel. He was with the Bureau for 21 years and is now director of operations at the Soufan Group. Welcome to the program, Mr. Ringel.
JEFF RINGEL: Thank you very much.
SIEGEL: When concerns come in about somebody like those expressed by Rahami's father in 2014, what does the FBI do with that?
RINGEL: There are three different levels of investigation that the FBI can do. The first one, the initial level - they're going to run the person's name or address through all the government databases to find out if that person is known to any of the federal agencies or other law enforcement agencies and for what reason. Also there are going to be interviews done, but there are restrictions on what can be done at the lowest level.
If at that level some of the information can be validated, then it will be pushed to the intermediate level where more investigative steps can be taken. And again if more information is developed and there's a possible nexus to terrorism or terrorist activity, then it gets pushed to the highest level where then the FBI can use all the investigative techniques that's available.
SIEGEL: When the Joint Terrorism Task Force first looked at this question of whether Rahami was worth pursuing further, what's something positive it might have found that would have led them to go up to the next level.
RINGEL: If there's information from our partners overseas or other intel agencies that pointed out that maybe an American traveled to an area that he should not have been. Other things would have been if Mr. Rahami's name appeared in other complaints from other people who said that he was making violent threats or talking against the government, therefore his name was more known to local law enforcement or reported more often in the government databases. That would have raised it also.
SIEGEL: Now, in this case, the man's father went to the police and said he thought his son was a terrorist, a statement he later retracted. How common is it for police over than the FBI to get somebody complaining that somebody in the family or in - on the block is a terrorist?
RINGEL: The FBI or the Joint Terrorism Task Force get hundreds of these type leads a week. Many of the leads that come in don't pan out. We've oftentimes found people using our system of reporting someone as a means to get back at somebody else. So it's not uncommon that the initial threat comes in, it's looked at, and then it doesn't warrant further investigation.
SIEGEL: The Rahami case, if indeed he did plant the bombs, has been remarkably successful given the amount of time that it took authorities to track him down and find him. On the other hand, I guess even more successful would have been somehow - what? - getting a search warrant and going and finding his bomb making equipment before he ever placed it? Is that conceivable to you that somebody could have put it together to get that far?
RINGEL: You're correct in that it would have been better to have stopped him before he did it. But at that time, Mr. Rahami wasn't on anyone's radar. If one of the neighbors who may have seen or heard Mr. Rahami exploding things in his backyard or heard him make statements and then contacted authorities, then there could have been an investigation on him. But at the time that this happened, Mr. Rahami was not known to law enforcement because there was no reason to investigate him.
SIEGEL: Jeff Ringel, thanks for talking with us today. Thank you very much. Mr. Ringel was with the FBI for 21 years. Now he's the director of operations at the Soufan Group. Transcript provided by NPR, Copyright NPR.