Looks like a funding dispute will be delaying the next step in the development of the new FBI building, according to this NY Times article.
The GSA has been looking into three possible sites, Greenbelt Metro site is one of them.
In august, The Office of Management and Budget (OMB) notified the FBI that there was no money in the budget to cover costs for the project, including what the government might pay up front to acquire the chosen site or to rent back the facility once it is built.
A congressional appropriation is an option, but unlikely. The developer could also be asked to include the cost of acquisition as as add-on, which will be charged to the government.
The report says that the final award is still on the schedule for next May, even the next step is going to be delayed.