Hart (Kiefer Sutherland) just keeps showing up, so the Feds decide to get Costa out of town on the next plane. Helping to pack his gear away and leaving him unattended, Duval hears a commotion and enters the apartment - to be shot in the chest.
It seems that Hart has dragged Costa to a car for a getaway, and Illeana gives chase. Travelling over a bridge, the car hints a barrier and Hart is thrown through the windscreen. Costa, unharmed, is determined to shoot him until Illeana pulls him away and the car explodes in spectacular fashion.
Costa calls round Illeana's that night for a bit of "how's your father" (got to love Austin Powers). Next day, Martin (the name behind the serial killer)'s mum is called to the station to ID the body. Hart is not the man.
Taking the elevator, Costa is waiting for her and kills his mother. Illeana makes it to the ground floor in time to find Costa standing over the body. She screams in disgust and fright.
Costa gets away onto a train, and is about to assume the identity of a baseball scout. Illeana is sacked for improper conduct. They piece it all together - Hart was just an art thief and was framed from the beginning.
Several months later, Illeana is living alone on a farm in the middle of nowhere - and heavily pregnant. Costa shows up. They argue, Costa gets violent again - and then graphically stabs Illeana's belly -- but Illeana calmly removes the blade and stabs the killer in the heart. She's been waiting for him and it's all a setup. She then removes a fake pregnancy bump prop, and calls it in to her old boss.