Again, good questions. It's true DNA doesn't lie. But it doesn't always prove culpability or innocence. A sample of DNA not belonging to DeSalvo was taken from Ms. Sullivan's body. It DID match that of the prime suspect in the case. (He had been introduced to her a day or so before the murder; but told police he had heard of her while she lived on the Cape.) Foreign DNA not belonging to the suspect and also not belonging to DeSalvo was also found on her underwear. So that's two DNAs independent of DeSalvo's that have to be factored into the equation. The young women living in the apartment had numerous male visitors, day and night, so DNA belonging to those guys would have been present on the premises. And it doesn't mean they're guilty...or innocent. Another factor is that there was never any other physical evidence nor eyewitness testimony to link DeSalvo to any of the crimes. If DeSalvo's DNA had been found on Mary's body, I'd agree with you. I am not altogether sure how it got on the blanket. Ten years ago, the state crime lab said the blanket was untestable for DNA.