I was contacted by one of the recruiters and told to call back and schedule a screening interview. After the screening interview was handled, I was told to contact the security lead to get a pres authorization setup to make sure I can be hired. I was also told to expect a phone call from one of the technical leads to get an understanding of my knowledge and experience level.

Slow process, but a lot of that had to do with their primary customer's requirements. Initial contact was months before an actual offer was made, and I was able to start work, but the customer was dragging their feet on external staffing. Company HR did the best they could, keeping me informed, but it was nerve-wracking.