Hence the name of the mosque involved with most of the terrorists that have struck us in the US:
Dar al Hijrah Mosque in Falls Church, VA
Since you mention Dar al Hijrah Mosque in Falls Church, VA, they were involved in the 2008 Holyland Terror Funding Trial.
“The process of settlement is a ‘Civilization-Jihadist Process’ with all the word means. The Ikhwan [Muslim Brotherhood] must understand that their work in America is a kind of grand jihad in eliminating and destroying the Western civilization from within and ‘sabotaging’ its miserable house by their hands and the hands of the believers…”
http://www.freerepublic.com/focus/f-chat/3315313/posts