I agree with SlapFish.

I think Fleet White was confused by Steve Thomas and company - that he grew suspicious of his friends because of the misinformation and opinion briefings he was getting from LE.

I don't think Fleet ever felt in his heart the Ramseys were the killers or he would have gone public and said so - - the man isn't shy.

I do think he was confused, and unsure enough that he allowed himself to be manipulated. I think he wrote the letters for his new friends, but I think he wisely held back and did not make any accusations, instead calling for the DA to be removed.