Ok, bear with me, this is my new theory.
Evidence is that he started a stilted conversation with Lilian in the car about the dogfight bust. Then quizzed her about whether Neil was a friend of hers.
So far, so weird stalkerish
Then, then, it turned to Darrell and how he had worked for Paul.....
Aha, I thought, he is indeed Very Bad, and now a Serious Criminal. Well..?