Man, this all lines up with my theory all along. I have a six-month age difference with BK and am also in the academic world. Things that are fairly common in this age=group/sphere: mental illness, drug abuse, loneliness, isolation, sleep deprivation, inflated egos, narc tendencies. With a list like that, it's almost impossible to avoid it all in some form or fashion. Granted, I am not a traditional on-campus-full-time student and am in a different (but related) field, so all of the above is just my own personal experience and may not apply here.
Just my first thoughts, all MOO and theorized based on my personal experience working in a criminal court setting, it was probably fairly easy to narrow it down to him once they had the car, between local DMV records or the university parking pass records. They may have even had the license plate the entire time, but they didn't want to tip him off. Once they got DNA testing back, they were able to get their probable cause in order. By not identifying the car directly, and maintaining they had no suspects, they got the tips they wanted while also not revealing their hand. There may have been concern among LE that he would be a suicide risk should he think they were hot on his tail. In which case, LE did a masterful job.
They may have even been monitoring him longer than the few days that is being
reported. They were also contending with court closings through weekends and two holidays. From my experience, even on higher profile cases, the holidays slow everything down regardless of if police are working as hard as they can straight through.
If anyone is curious, here is the relevant
statute for the Burglary charge:
"18-1401. BURGLARY DEFINED. Every person who enters any house, room, apartment, tenement, store, shop, warehouse, mill, barn, stable, outhouse, or a building, tent, vessel, vehicle, trailer, airplane, or railroad car with intent to commit any theft or any felony is guilty of burglary."
It appears that Idaho doesn't have a separate "breaking and entering" or "forced entry" charge. Some states have a separate charge, but others absorb it into their burglary charge when forced entry happened simultaneously with the commission of a felony. From my quick analysis of the Idaho statutes, the rolled together charge is consistent with what Idaho does. They do have a separate
trespassing charge, but the key difference is that the Burglary charge is triggered by the intent to commit a felony. So, we still can't deduce whether he broke in or if he at some point had an open invitation into the "party" house. I think that will tell us a lot about his relationship to Xana, Ethan, Maddie, and Kaylee.