It is astounding that at one time, more than 200 agents from the FBI and other federal and state agencies were combing the hills of western North Carolina looking for Rudolph, but the search was cut back after four years of fruitless searching. The very wooded area where the FBI had confined their search was exactly where he had lived for the entire five years he eluded the FBI.

 
3. Elizabeth Smart is another example of a seach that was conducted over a year with no results (she was recognized by a citizen at a rest stop on the highway in Utah, not found by the FBI).
 
Other cases:

There are dozens of other prominent cases like this where the FBI and hundreds of other search agencies in the US could not find a victim or suspect. US investigative teams have further distinguished themselves in their (up to now) futile searches for the terrorist Abu Musab al-Zarqawi and for Osama Ben Ladin.

In the light of a review of these experiences, perhaps it is easier to understand why the Aruban and Dutch authorities are not as eager to have FBI assistance. And it is perhaps easier to understand that not every case is quicky solvable.