I used to live very near there and I always heard that it was someone underage and disabled, but being somebody's cousin or whatever absolutely tracks.
It's hard to explain how remote it is out there and how few people are around. Harvard has less than 1000 people. That's like 1/3 the size of a cruise ship. If you stand at the edge of town, you can see the horizon in nearly every direction.
I guarantee you that everyone in Harvard knew exactly who did it within the week. The rest of us will probably never find out. That's how it is out there. There's not much in the way of legal authority and a lot of shit just gets "handled" behind the scenes.