Yes, there are probably more.
Congratulations to the inter-jurisdictional LISK Task Force who investigated deeply enough and accumulated a mountain of evidence to force Rex to confess. The evidence against him was overwhelming, thanks to a lot of officers who are very skilled at using data to hunt killers. Thank you for digging through every last file until you found the mention of the green Avalanche pick-up truck and the john who looked like an ogre. Thank you for sifting through all that cell phone data to find the relevant burner phones, then tracking them down to Heuermann.