Tracking and identifying persons in videos are important building blocks in many applications. For browsing of multimedia data or interactive investigation of surveillance footage it is not even necessary to uniquely identify a person. Rather it often suffices to find occurrences of a person indicated by the user with an exemplary image sequence. We present two systems in which the search for a specific person can be initiated by a sample image sequence and then be further refined by interactive feedback by the operator. In the first system, episodes of TV series have been processed offline and can be searched for occurrences of the different characters. The second system tracks people online in multiple cameras and makes the sequences immediately searchable from a central station.