It's hard to know for sure. For whatever reason, I don't think the W's and Rita were close enough they would have shared their plans to kill the Rhoden/Gilley family. Rita probably saw and heard a lot before the murders that, afterwards, made her realize who the killers were. That may have been the case with a number of people close to the families and explains why LE kept pushing people to talk. Early on, though, the people everyone thought had information actually didn't.
There's something about the way attention was diverted from the W's for so long, the way they received sympathetic media coverage to indicate FW did figure it out after the murders and did her part to divert suspicion elsewhere. We all know Angela spent a lot of time and effort on it, she was the most visible defender.
How do we know that LE were diverted onto anyone/group other than the W's? My guess is that they had to follow certain potential ideas/suspects til they eliminated them.
I believe that JW would have been in that group from day one. LM said child custody in an online news video at the very beginning. BCI had an obligation to follow any leads the W's gave them but they kept their eyes on the W's that first year too. jmo