Castel

Castel is a supporting antagonist in The Bourne Identity. He is one of the three "assests" sent to by Alexander Conklin to kill Jason Bourne.

Events of The Bourne Identity
In Bourne's old apartment in Paris, Bourne senses someone is coming towards him and Marie asked him is something wrong, then suddenly, Castel breaks in by shattering the window, shooting his sub-machine gun. He then take out his knife and engages in a one-on-one fight with Bourne, who counter with his ball-point pen. Castel was stabbed in the hand with a pen. Eventually, he was worn out in the fight, after Bourne had the advantage.

Bourne then interrogates him who is he, while Marie is searching Castel's bag, she was shocked to see wanted posters of Bourne and her. As Bourne goes to Marie to calm her down, but Castel jumps out of the window to kill himself before Bourne could ask him again.

And as it turns out before the fight, the concierge who was talking to Bourne earlier was found dead downstairs.