My question uses the word "should", not the word "could".
Because it sounds like you are saying that the investigation of Abdi Zullah should be permitted to circumvent the courts because the courts and the protections that they rightfully confer would not permit the violation of Abdi Zullah.
It sounds like you think the 4th amendment is great under 'normal circumstances', and it sounds like you think that "terrorism" and "I've got a hunch" should be a secret password for a process that circumvents it.
If this is a misunderstanding, then I do not seem to be the only one misunderstanding you. You should work on your delivery.
For law enforcement? Yes, at least to the extent that an "unreasonable" search would be performed.
For military applications (such as, yes, counter-terrorism)? No, for the same reason we didn't get a warrant to wiretap Hitler's generals. I would still say that searches against any particular individual be supported by more than a single analyst's "hunch", or that non-individualized searches should be looking for particular things instead of just trawling what they can, if only for resource efficiency reasons.
(Many people, myself included, think that there is something wrong with how we are currently handling those situations, but search warrants for non-citizens outside of the country are obviously not the answer we are looking for there.)
Domestic terrorists? Get a warrant.