I wonder if the reason this evidence was just discovered has to do with the pace of discovery in the case? Why is this just being discovered 6 years later??
I think what Greer is referring to may be *microscopic* evidence of vaginal epithelium, or cervical or uterine menstrual tissue. Vaginal epithelium is different from skin cells. Here's some brief info from non-scholarly sites (lol!):
http://www.wisegeek.com/what-is-vaginal-epithelium.htm
https://www.plim.fr/en/content/19-about-menstrual-blood
Also, remember that the narrative and documentation in RZ's autopsy regarding genital/ sexual assault exam was severely lacking in thoroughness, given the circumstances of her death and investigation at the time, IMO. There was not even a mention of the condition of her cervix-- whether it was parous or non parous (indicating childbirth), or traumatic/ atraumatic. There was an "assumption" that she had intra cycle spotting from her IUD, or that she was on her menses, which caused the droplets of blood in the shower, etc. There was not enough "exam" done and documented in her autopsy, IMO, to rule that in, or rule out anything else that could have caused the vaginal bleeding.
Anyway, the new knife evidence is interesting, and relevant.
Is this the same knife that was presumed to have cut the rope? The news article says "steak knife". Do we know where this was found?