Fire crews were called the Landing at Cannon Branch in Manassas, a new development on Gateway Boulevard behind the Manassas DMV.
From a press release:
At midnight on May 20, 2018, units from the City of Manassas and Prince William County were called to 10464 and 10466 Ratcliffe Trail for a two-alarm fire. These were unoccupied dwellings still being built. One of the units had a major collapse on the third and fourth floors.
The Fire Marshal is on the scene to determine the cause.