Amster, just to address your speculation:
Maybe I'm misunderstanding, but Rodney would never have gone to high school with TLM; there's a big difference in their ages. I'm not sure if TLM even went to high school, or was educated to an extent at the various detention centres she was in.
It was pretty well known at the time that RS thought that Tara's friend, SL, was involved and that perhaps the two women were in it together. The reasons for this weren't made clear, but rumour had it that RS and his brother parked all night in front of SL's house not long after Tori disappeared, hoping to see something that would lead them to his daughter. I don't know if RS and SL went to high school together, or if he was then talking about someone else. Tara would never admit, even to herself, that SL would be involved. Anyway, these were just rampant rumours at the time.
JMO