You are talking about the Dar AL Hijrah mosque at 3159 Row Place, Falls Church, VA. That would be the windmill shaped building 700 feet from the Home Depot where the FBI agent was murdered.
The mosque/islamic center is where this group of eleven were said to meet to hear lectures by an Islamic lecturer: Ali Al-Timimi,
The Michael's craft store that Muhammad/Malvo visited twice earlier in 2002 is also in the same shopping center, so in my opinion, M&M must have visited this mosque in January and August 2002. I would even bet they ESCAPED to this mosque after the murder...
And with the LEADER of this group of 11 jihadists ALSO being a black Gulf I war veteran, Washington State native, and Islamic convert, I have to assume they met at some point and knew each other.
If this aerial photo doesn't show up try the mapquest map here
As for your question, I think Freeper angkor answered it on another thread:
- It is well-known that the dominant Muslim theology in Northern Virginia is Saudi Wahhabism, from the Dar al-Hijra mosque in Falls Church, to the phony "charitable foundations" Herndon, to the Graduate School of Islamic and Social Sciences in Leesburg.