E157: MURDER - The Phantom of Heilbronn

In 2007 two police officers are shot in their car, only one survives. The police search for a mysterious woman, who's DNA is not only found at this location, but on more than 40 other crime scenes during a span of 15 years. But who is this criminal mastermind, and is she responsible for the murder of officer Michèle Kiesewetter and 5 others? Or is someone else the culprit?