difficult to introduce human agents to the groups; it is more likely that human intelligence can be gained by subverting someone who is already a member, or perhaps is indirectly associated (e.g., a banker or arms dealer). Efforts to use HUMINT operations with non-official cover, especially in the areas outside the groups' staging areas, have been disappointing. Stepped-up efforts to use non-official cover, especially in Europe, began by creating covers in investment banks and consulting firms. Only several years later was it realized that terrorists would have little to do with such organizations. Another realization was that, even with excellent cover, HUMINT successes would be unlikely to recruit people deep inside the terrorist cells. Where HUMINT had more potential, and where the cover organizations needed to change to help find appropriate targets, was on the fringes of the terrorist organizations, either groups from which the group would need goods or services, or from people with awareness of the groups but not supporting them. For example, there are reports that 15 cargo ships are linked to al-Qaeda, whose activities at port might draw the attention of security officials, or even low-level dockworkers or craftsmen. Another potential target could be moderate Muslims that do not want to take up an overt role against jihadists, but could supply information. The cover for approaching such persons could be any of a wide range of businesses and institutions. Foreign specialists in explosives, WMD, and other warfare methods might be noticed by the CIA in their countries of origin. By tracking their movements, the specialists-for-hire might lead to trusted persons within the groups. Once a member is identified, other intelligence collection methods could be directed at his communications, surveillance of his home and place of work, etc. There has been significant controversy, without there being classified Congressional views, over the use of black sites for interrogating suspects, as well as the Guantanamo base. A separate role is played by regional Counterterrorist Intelligence Centers. SIGINT Signals intelligence, or SIGINT, is a common tool in espionage, although it has been hard to apply to anti-terrorism activities. The National Security Agency (NSA), the organization formally responsible for SIGINT within the United States intelligence community, was used to targeting conventional military communications systems, while terrorists lacked dedicated communications systems, confronting the NSA with the prospect of "picking out the needles of terrorist transmissions in the haystack". While some information has