The Soufan Group's latest briefing ends with a passage that explains why the public will find it difficult to get information, let alone having the motivation to communicate this:
Terror cells composed of family members present tremendous challenges for intelligence and security agencies to infiltrate with human sources. Such tight-knit groups are loathe to bring in new people, since the trust is so tight among the existing members. The sense of loyalty stemming from familial or matrimonial bonds makes it less likely that one of the members would inform on the others; the betrayal of the group is made much worse by obligations to the family.
Link:http://soufangroup.com/tsg-intelbrie...ies-of-terror/