Well I was just talking to my mother-in-law the other day about this, and she stated that she heard he was having an affair, and Mrs. Roseboro probably found out and confronted him wanting a divorce, plus it was said that the Father of Mr. Roseboro told his son, if he has extra marital affairs that would bring shame to the family that he wouldn't be left with the funeral home business when the father retires or pases away.
So after hearing this, I definately think Mr. Roseboro killed his wife and tried to make it look like somebody else did it, so he wouldn't lose his chances at being owner of the funeral home business, plus he probably had a large insurance policy on his wife, and by killing her he could collect and avoid child support if she divorced him, and nobody would of known of the extra marital affair, if the woman he was having the affair with didn't come forward.
Oh and that L shaped instrument that the police think she was hit with probably was his tire iron, and another theory is he could of been found to be gay like his brother from what I hear, and his wife found out and he wanted to stay in the closet so to speak.