Federal investigators looking at what caused spacecraft's deadly crash wrap up site work

Federal investigators who have been in the Mojave Desert trying to find out why an experimental spaceship crashed are wrapping up their work in Southern California.

National Transportation Safety Board spokesman Peter Knudson says that on Friday, investigators are leaving the area about 120 miles north of Los Angeles where Virgin Galactic's SpaceShipTwo broke apart a week ago.

The safety board will take months more to finish interviews and analysis of physical evidence before publicly stating what it thinks caused the crash.

SpaceShipTwo was destroyed after its feathering system that controls descent deployed prematurely and aerodynamic forces ripped it apart. The co-pilot was killed, and the pilot was seriously injured.

Virgin Galactic is building a replacement spaceship and says test flights could resume as early as next summer.