Just wanted to say that there is an idea taking hold on this thread (and in other places where people discuss this case) that there was something unusual about the DNA that was found, and it could be dog DNA or something along those lines. IMO this is not what LE has said. The former chief prosecuting attorney said that there was a lot of crime scene evidence, and some of it was odd, and it was not what one would expect. He is talking about the totality of the physical evidence at the scene, he never said that DNA evidence specifically was odd. In fact, he never confirmed the presence of DNA at the scene - other LE members have done that.
The first piece of big information that we heard about the crime scene came from former chief prosecutor Ives in Down the Hill podcast, episode 3 "Signatures." In this podcast, he tells a reporter that the crime scene evidence was odd.
Reporter: What do you mean by odd?
RI: Well, in one sense any murder scene is probably odd. But again, this is where I have difficulty because I'm not sure what all has been released. But there were a variety of things, at the scene of the crime, where - I guess I would ask you to talk to the State Police about that, they have to decide what is going to be released and what's not going to be released, but it was just not your normal "a person was killed here" crime. That's all I can say about it....All I can say about the situation with Abby and Libby is that there was a lot more physical evidence than that at the crime scene (note: he's talking about a previous example he gave of a "normal" murder, which is a domestic violence scenario) and it's probably not what you would imagine. What people think I'm talking about, it's probably not....I do think it will be solved because it's so odd, and so unusual, and people are so compelled to talk about the horrible things they do.
I'll also pull forward a transcript of an interview Robert Ives did with HLN, where he talked about evidence at the scene. He says that the large amount of physical (not biological) evidence at the scene led everyone to believe it would be solved within 2-3 days, and IMO it's clear from his comments that the prolific evidence that he is talking about was not DNA. Whatever evidence it is that LE thought would solve the crime right away is something that even police in the 1960s, prior to DNA investigative techniques, would have been able to use to solve a crime:
RI: There was so much physical evidence of the crime and the crime had been found so immediately after it had been committed that experienced investigators thought it would be solved really quickly and normally it would be. It’s shocking that it hasn't been solved today.
In today’s world we have cell phone evidence and DNA evidence but if you had been a police officer in 1960 and had arrived at this scene with the traditional physical evidence that was there - not to mention that we had video and audio of the person I think certainly killed the girls - you would be certain you were going to catch them within 48 hours.
So when you add in that we have evidence today - or investigatory methods that we didn’t have in the 1960 all police officers - I believe anybody who was involved - had any doubts that it would not be solved within 2 or 3 days.
Interviewer: Just from the evidence at the scene?
RI: Yes, due to the circumstances of the crime.
IMO because so many people have pets, finding animal DNA at an outdoor crime scene would be the least odd thing about it. Animal DNA could have been part of the "large amount of physical evidence" at the scene but it's clear from Ives' comments that the really odd evidence is not DNA in nature.