Police activity shuts down parts of I-495 in Fairfax County

An investigation is underway on Interstate 495, causing major delays in Fairfax County on Sunday. Police activity has shut down all southbound lanes on Interstate 495 between Gallows Road and Little River Turnpike. Officials say emergency crews responded to reports of a vehicle collision and stabbing on the interstate. Traffic is currently being detoured at Exit 50a onto Route 29/Route 50. Officials have yet to release further details about the investigation. This is a developing story. Check back for updates.