What & Who discovers terrorist plots?

[davidbfpo]

A NYT article on whether the warning by Ahmad Khan Rahami’s father to the FBI that his son should be of interest:http://www.nytimes.com/2016/09/23/ny...-bombing.html?

This is not a "black -v- white" matter:

While Mr. Rahami has spoken briefly about his contact with the F.B.I., the interviews this week provided his most detailed public account so far. His description of that contact differs starkly from the one given by law enforcement officials, who on Thursday challenged the father’s account, saying he did not provide the F.B.I. with many of the details about his son that he now says he did.

Worth citing NYPD's response in full, given at a Congressional hearing this week:

John Miller, deputy commissioner of intelligence and counterterrorism for the New York Police Department, outlined the challenges facing agents as they investigate such cases — especially given the number of people they look into and the threshold that must be met to take action. 'If you have that many contacts with that many people over that period of time, it’s increasingly likely that the next time something happens, it’s going to involve somebody that you knew, heard about, investigated, bumped or otherwise checked out. Now, that’s a good thing in that, when you’re assessing who to look at first and they come up in those records, it gives you a basis to go forward. It’s also a liability in that people have somewhat of a misconception about our ability to put someone under surveillance, leave them there indefinitely.'