kemo-
Think about this- what if you replace "Asian male" with female prostitute in this discussion. A fifth female found directly in the cluster of the GB4. Would you then suspect the cases are related?
If you do, then I don't think you should completely discount my theory. The killer of the GB4 is likely to have deep sexual identity and anger issues, and a cross dressing male may be someone he would encounter, intentially or otherwise, in his lifestyle.
This is just the way I'm thinking, waiting for more information to come in.
The Night Watchman
But as far as I read, the COD is different. Blunt force trauma, is that correct? Now, that doesn't mean 100% this case is connected or unconnected, but lets speculate a moment:
What, if the killer has NO deep sitting sexual identity issues. In this case, finding out, the girl he expected is a male, would react with disgust and rage. It would be a fast uncontrolled kill, for example by blunt trauma to the head. By my experience, there is a subtle difference in the behavior shown by the killing method and thus, I plead to make a difference between the words "power" and "control". Beatings, including kill by beating on the head, is power assurance/power gain. Typically, we would find that method of killing in disorganized or temporary raging serial killers. Take Ted Bundy as an example (I love him as example because everybody knows something about that case): Some of his vicitms were strangled, others beaten to death. But if you hold the timeline of his normal life against the timeline of his murders, you can see, that he usually beat his victims to death in phases, in which his regular life was rather chaotic and, of course, in the times of his spiraling down (that includes specifically the Sigma Chi murders). Means, there are serial killers known changing especially between beating to death and strangling, and the reason why those appear sometimes less organized is rage, but it is normally temporary rage unless you deal with someone really on the absolute low end of the organization scale.
Strangling on the other hand is more common. BTK, Bundy, the Hillside Stranglers ... all stranglers. Strangling is control assurance/control gain. It alows to control the death of the victim, it is a lot more upfront than beating. The difference between power and control is, power is the "cure" against feelings of helplessness or rage, control points rather to sadists or deeper sitting inferiority complexes. At least in serial killers. Spree killers with inferiority complexes, due to the shorter time/kill ratio go normally for firearms and force their victims in kneeling positions (the equivalent for SKs for such poses is staging as for example in at least one of Alcala's murders).
So, pure from the behavioral point of view, I think, your theory is possible, but the rush kill of the male doesn't point to sexual identification problems but rather to disgust because this guy knows exactly what his sexual orientation is and felt disgusted.
