I don't think the drifter/narrative works at all.
High Risk offender is a word/concept I forgot in all my amateur musings earlier, that I learned. Extremely motivated and high risk,
Low risk offenders, think of a burglar who notices an open window in empty house, or the rapist, who merely has to roll over and rape someone who is drunk or passed out next to him, those are relatively low risk crimes, (in the offenders mind)
Running in a house in the middle of the night, and killing 4 with a knife seems like it was planned, and thought out to some degree.
Oh, and someone mentioned Jack the Ripper, I mean this with no contention or animosity, virtually no serious "Ripperologists" believe he was royalty, that is wild and totally absurd (but sexy, like these theories always are) theory. He was most likely an alcoholic who lived in the immediate neighborhood, and was of the same or near same social class as the women he killed. He wasn't a doctor a surgeon or a prince.
In the Knox case, there was a murder/stabbing and I believe strangling but the motive was to control the victim, then as an afterthought, I believe sexual assault, but the person entered the home to burglarize it.
Why does the offender enter the home? If he brought a K Bar knife, the intent must be murder. The target was one woman, and the rest killed to cover up, or because they were potential witnesses, or did he mistake one woman for another, in the confusion? There's going to be a link to the victims here.
A man who was studying for a Ph.D. at a nearby university is charged in the stabbing deaths of four University of Idaho undergraduates. Many questions remain.
www.nytimes.com