Episode 1: The Spiritus Murder - S1.E1

The experts investigate the case of Melissa Ulrich. On May 23rd 2006 the 19 year old Melissa dies in a gruesome way in a fire in her apartment in Arhem. The fire appears to be lit by someone else so the Police is hunting down the killer. Who was able to tie up this defenseless woman and pour her over with Spiritus? Why is her boyfriend one of the suspects for a while and which person from is group of friends appears to know more about this crime? What happend on that Tuesday morning?