The Ending... what makes sense and what doesn't.

I saw this movie over ten years ago, and liked it a lot. Watched it again this afternoon and loved it.

People have questioned the consistency of Oaks' character when it came to the dying confession. I just assumed the crappy tape-recorder wouldn't even pick up his last whispered breaths (I don't care if that brand was chosen because it says "hi-lo mic sensitivity"). Nevertheless, Oaks' motive for talking, I thought, was pretty obvious: come clean, so that Tellis keeps the truth buried. Tellis pleads with him to the effect, "you gotta tell me what happened, man."

Tellis, in this moment, doesn't really give a **** about Calvess, a dirty cop who sold guns, badges, and undercover identities, including Tellis's. Oaks' confession makes Oaks look good -- he's the concerned father of an adopted child, not a murderer; combine this with the fact that Tellis just put a couple fatal bullets in him. If Oaks had murdered Calvess, then it makes Tellis' job a lot easier. However, if Calvess topped himself, and Oaks ran around trying to help the widow, then he's a much more sympathetic character.

Now here's what doesn't make sense, and I hope I missed something: Why in the hell is Oaks pressing for an investigation? He had the toxicology report doctored, and the widow is presumably receiving a pension.

One explanation is that he blames drug-dealers for turning Calvess into a junkie, but that doesn't hold any water, and flatly contradicts the flashback in the confession where Calvess turns the gun on himself.

Another explanation is that Oaks is just plain "unstable," but there's a difference between unstable and actively pursuing what can be your own undoing. It doesn't make sense for him to behave so rationally irrational.

I'm just not sure why he'd doggedly pursue killers he knows do not exist. It's almost impossible to believe he's that dumb.