To the Limit (1997)

This Spanish-French thriller is set in Madrid where late-night radio talk-show host Elena gets a call from serial killer Javier Barea who claims he will kill within the hour. Lawyer Maria Ramos is listening to the radio and immediately assembles an investigating team that includes Javier himself. Maria begins to suspect he's the killer, but she is simultaneously attracted to him. How long until she becomes the next victim?