Film starts with a scene from its end. As best as I can recall, a military? man in a room sitting at a table is shot. Film then goes back in time .... there are scenes where a computer is continually refining an image on the screen so that a spy? can be identified. Eventually the opening scene is is then repeated.
TKS
Does sound like No Way Back except in the opening scene no-one is shot, he's being debriefed, there are cameras running behind a two-way mirror. Wonderful film, Washington by night never looks the same!