You guys are probably not going to like my theory. I'm approaching it from a different angle. I just joined Websleuths for the Fiore murder case, but this mysterious disappearance did catch my eye, especially when they found her body inside a wall in the same building.
Here's how I've been looking at it. I haven't read about the loves in her life or the rivalries she's had at school, so I looked at this without assuming it was some kind of domestic squabble.
Firstly, since she disappeared inside the building and was found dead inside, I assumed it was an inside job. Who would know about such a place to conceal at body? Janitors, professors, lab technicians, students.
They mentioned they found her blood on clothing that wasn't the same clothes she was last seen wearing, so I thought she might have been either convinced to wear it or she was put in it in an unconscious state. I figured maybe this was some hazing ritual gone bad, or a sorority prank gone bad, considering it was also pretty close to the beginning of the school year.
It wasn't until today I thought of something else more sinister, related to the occult. The date she disappeared was a day before an important date in terms of numerology for satanists - September 9, 2009, or 9-9-9. I'm not very knowledgeable when it comes to such things, but I do know that the number 9 has significance for some occultists. If the time of death comes back, and they can accurately pinpoint it, and it's find out she died within 12 hours of her disappearance, or close to 9am-9min-9sec, if not at midnight on 9-9-9, then that will give more credence to my theory. I doubt she was alive more than a day if she was in the building that whole time. It would be hard to keep someone prisoner, unless they built secret rooms into that place.
We're talking about Yale here, not just some regular community college. They have a long history with secret societies and such. Perhaps she was targeted because she met their requirements, such as someone who has abstained until marriage? Maybe the clothing she was wearing (i.e. put in) when killed is significant, in addition to the method she was killed or bled out.
I know that all sounds simplistic and something out of a cheap hollywood script, but it's a different way to look at the case and the motive for murder. If you know people on this forum who are knowledgeable in occult murders relating to satanism, you should ask for their input as well. Check out the significance of the number 9 and the three 9s.
That's just my 2 cents.