The episode summary above is incorrect. Whomever wrote it must not have been paying close enough attention.
The man's wife is not the next victim of the killer, but rather she herself is the killer. Apparently, this older couple are quite moralistic, and do not take well to their daughter's rebellious ways, prompting the daughter to run away. It is alluded to, if I recall correctly, that the daughter got into stripping or something similar in order to make a living. She gets killed, as do two other young women who live a similar lifestyle. The father realizes this, and attempts to tell 2 lawmen and one priest that he knows who the killer is, even hinting at the fact that his wife killed their daughter. The priest gets very offended by this thought and writes the father off as delusional. The cops don't believe him either. He goes back home only to see that his wife is in her 'moral avenger' state of mind again, and that she will therefore kill at least once more.
A pretty good installment, but the father/husband is quite painful on the eyes - it was hard to keep looking at him, and he is in every scene. Oh well.