So if BK were to have completed his PhD, it would’ve taken approximately three more years then? Or can that vary?
Now I’m wondering if he assumed he would be getting away with these murders, then what next? More murders? To him, were these, and any potential future murders, valuable as research in the pursuit of his PhD, just as much so as they were also clearly a thrill for him?
Eeek. Scary combo.
It can definitely vary. Different PhD programs (and even different universities) can require a different amount of coursework that has to be completed, and some programs will allow you to count courses you took as part of your Master's degree towards the doctoral work (which is the case at WSU per the program's info page). Once the coursework is done, the speed at which you complete your dissertation and sit for your exams (if required) varies by the individual person.
This is from the info page for the doctoral program in Criminal Justice at WSU (link below) -
"The Doctor of Philosophy in Criminal Justice and Criminology is available on the Pullman campus. A student aspiring to earn a Ph.D. degree should
expect to spend three to four years, depending on the individual,
in study and research beyond the M.A. degree, of which
at least two years must be enrolled at Washington State University, and
at least two consecutive semesters must be spent in residence as a graduate student in criminal justice."
So, what we can say for sure in BK's case is that the doctoral program he was enrolled in requires students to be enrolled as a WSU student for at least two years, and of those two years, they have to be on campus for two consecutive semesters. Since he was there in Fall 2022, he would have to have been on campus for Spring 2023 as well. Depending on how many courses he took in those two semesters, and any possible credit given for courses he took as part of his Master's degree, it's possible he would have left the university at that point as you can finish your dissertation from anywhere (physically, I mean). You just have to come back for comprehensive exams (if required by your program) and the graduation ceremony (if you want to).
Doctoral Program Info Page