Trivia: The movie was originally scripted with a male lead and Tom Cruise was approached to play the title character. Ultimately, he backed out and the script was rewritten with a female lead and Angelina Jolie took the role.
Trivia: In the scene where Salt jumps off the subway, the dark and heavily guarded station is supposed to be the 51st Street Station on the IRT Lexington Avenue Line in Manhattan, the nearest station to St. Bartholomew's Church. However, it is recognizable as an IND Station by the thick tiled columns, indented green-striped walls, and the wider train, and is in fact the Hoyt-Schermerhorn Station in Brooklyn, with its signs covered by the number "51". (00:46:40)
Trivia: Orlov's "hideout" is on a scrapped ship located in a 'bone yard' of other scrapped ships waiting to be dismantled, etc. This 'bone yard' of ships is located at a landfill site on Staten Island - I believe the name is the "Fresh Kills" Landfill. This is the landfill where debris from 9/11 was taken, and can briefly be seen in the background of a few panoramic shots.
Answer: They have to at least investigate that kind of an accusation, and when Salt so vigorously resists arrest it basically confirms, in their minds, that she is in fact a spy.
Phixius ★
I actually kind of find it shocking that they would be willing to believe a guy who would do or say anything to save himself and since Salt was with the agency a long time, they could have at least given her the benefit of the doubt.