An interesting case - what was that police officer doing where it appears he is rubbing his finger over the point where the DNA is claimed to have been found? Given that the car wasn't swabbed until two months later, it might be totally irrelevant - it's not clear whether the rubbing of the car happened at the time the body was found or when the swabbing was happening.
The lack of any DNA belonging to either of the two suspects in the ligatures is odd as well, especially given the material from which two of them were made - the hoodie string and the bungee. I haven't had a chance to see what else is available about this case - will do that when I get home from work.