Emily Prentiss was a former Supervisory Special Agent with the BAU who joined the team two episodes after Elle Greenaway resigned from the FBI for good. At the end of Season Seven, she resigned from the BAU and later accepted a position with Interpol in London. She was replaced by Alex Blake, who held the position until her own departure at the end of Season Nine. The position was then taken over by Kate Callahan for the duration of Season Ten before her own departure.