It was in the article where his professor called him a genius.Whoa, that's very strange! Source?
Although I will say that a PhD does not necessarily require a master's degree for admission. In my case my PhD admission was based on my bachelor's degree because, although I had a master's degree, it was in a field different enough that they were more comfortable admitting me to a PhD program that was closely relatedto my BS.
In many fields a masters is simply a failed PhD and given as a consolation prize. Not knocking anyone with a masters degree, just saying that academic things are not as simple as most of the public things.
If looking for his academic work, you generally have to pay for master's work to be published which is a bit of a scam so most people don't. The library at the school you get your degree from almost always gets a free copy so that is the place to look. Almost any PhD requires creating "new knowledge" in your field and that means any research library will want a copy. You don't get to sell it to them but your work is "published" for free and sold to libraries, not as a physical book but as access through a database.
ETA: Source: personal experience through 4 graduate degrees and 20+ years working at a Tier I Research University.
Let me see if I can find it.
Edited to add
Idaho 'killer' a brilliant student, says his criminology professor
DeSales University Professor Michelle Bolger said she's in absolute shock after hearing that her former student Bryan Kohberger is the accused Idaho quadruple murder suspect.