"Once you have eliminated the impossible, whatever is left -- no matter how improbable -- must be the truth!" -- Sherlock Holmes
Since DW couldn't have dumped the body, DW didn't do it. Which means, like it or not, LE falsified evidence!
It's not so improbable, really. It is certainly consistent with the motivation LE displayed when deciding which evidence to look at and which to ignore. They wanted him found guilty, and they made sure he would be convicted!
A Sprinkle and a smear, and a promise not to tell. They probably thought they were being secret heroes.
?Yet you are using there evidence to prove Westerfield didn't do it. Are they lying only when the evidence works against ?