Rent Eye of the Beholder (1999)

Ewan McGregor stars as "the eye", an isolated British intelligence officer assigned the case of the enigmatic and mysterious Joanna Eris (Ashley Judd). Joanna is accused of blackmailing a senior British official - but she is more than just a blackmailer. As the Eye begins his task of shadowing her he discovers that she is capable of more than just extortion. A master of disguise she is also a lone killer who anticipates his every move and stays one step ahead. As he follows Joanna from murder to murder he feels compelled to watch her, becoming more and more obsessed with what he sees. The closer the Eye gets to Joanna's life the more dangerous his fantasy becomes. Who is more dangerous the hunter or the hunted?