Spoilers all the way through.

Here's a theory and I'd like to hear maybe why I'm wrong but could the killer be Taylor Kitsch' character Officer Woodrugh?

So I'd really enjoy it if the killer isn't the mayor's son or Rick Springfield and be something of a shocker unlike season one. I think there are some elements which could point to officer Woodrugh as the killer.

Whomever shot Velcoro didn't intend most likely to kill him. Now despite the fact in real life it very well might have this leads to a great many possibilities as to who the shooter was. Assuming the shooter and killer of Casper are one in the same -- they both wore the mask -- might it have been Woodrugh not wanting to kill Velcoro because he doesn't actually want to harm him? It was someone who also understands how to handle weapons quite well and who had access to ammunition for which cops have access. We know it wasn't Dixon.

The person behind the mask which led Velcoro and Bezzerides was also someone who was in very fit physical condition. Assuming of course this person and the killer and the shooter are all one in the same this could potentially point to Woodrugh as well. One might think the man who gave chase wanted to plant the car and tie it up with the employee but to me it seems he wanted the other detectives to notice. He might have started the fire to get their attention hoping they would notice hoping his distance and superior physical fitness would allow him to escape.

Why would the killer want those two detectives to notice and follow him? Well Woodrugh's past is mentioned quite a bit, but we know almost nothing of it. Perhaps Woodrugh wants Bezzerides and Velcoro to believe there is a wider conspiracy worth following with their investigation. There are a great many elements in Vinci which are completely corrupt. The Government, Vince Vaughn's character, and business itself such as the Catalyst group. Woodrugh wants to exact revenge on Vaughn's character Frank specifically as well as the other elements in Vinci.

Why was Dixon following Woodrugh? Was he trying to make an extra buck taking photographs to sell as paparazzi? No he was tasked by the mayor and or the Vinci PD to retrieve damaging evidence such as that on the video Camera and the criminal events surrounding the mayor's son, prostitution, drug use, those odd cult like parties with people in high society. Dixon's prime goal was damage control for Vinci. In doing so he began to suspect Woodrugh and reported as such to the mayor and the mayor and or Vinci PD along with Dixon set up the raid so that Woodrugh, Velcoro, and Bezzerides should all be killed. Velcoro is not their man. They don't entirely trust him. Dixon was completely corrupt and entrusted with much more.

We've been led down this path where like last season we want to connect this all to a mythology, to systemic corruption of that higher than the town of Vinci. And while that might and probably does exist it's a red herring. Woodrugh is behind the killings. Why? Frank is his father. The Catalyst group has some shady dealings related to his service in the middle east, and Woodrugh has a hatred for the vices of Vinci and its government.

So wait how could Frank be his father. Ok maybe this one seems really like a stretch but we don't know who his father is. Paternity seems to be such a huge issue in this series. Frank is attempting to have his "first" kid, but we know he can't because his wife cannot get pregnant. Frank really wants a son, and one that is his own. Velcoro is the opposite here. He doesn't care about paternity at least not genetically. This is a great heroic element of this character and why Woodrugh respects him. Whomever is attempting to ruin Frank is doing so not solely out for the purposes of monetary gain but revenge. Woodrugh...also often referred to as "the kid" knows Frank is his father and is disgusted with whom he is and the horrible life he left him with. I think Woodrugh's character is mean to be younger than the actor. And Vaughn could potentially be in his late 40s or early 50s. It's entirely possible for Frank to be his father in this universe. Woodrugh's mother may have been a prostitute. Frank may have raped her. There are a lot of possibilities here. Notice Woodrugh is willing to sacrifice everything about his self interest -- his latent homosexuality -- for the hopes of raising his own child. We tend to think that Woodrugh's uncertainty and fear regarding his own sexuality is what drives his urge to get married and raise his child but it could be strongly related to an absent and potentially terrible father figure as well. This lends well with the whole Oedipus Rex similarities that there are supposed to be with this show. Frank all along is searching for who killed the king when it was him or his actions all along that did it. Or perhaps Casper was Woodrugh's father.

So why with all this being wrapped up would Woodrugh want to be on the taskforce again? There's far more corruption worth following. Woodrugh wants the Catalyst group to come down. Frank isn't completely taken care of either, nor is the Mayor, his son and the town of Vinci and this secret society which probably rapes and murders women. Woodrugh wants to expose much of this. He wants to get away with the murder -- as in not go to jail -- but he wants to exact revenge much more.

Any thoughts, am I off my rocker here?

TLDR; Kitsch's character Woodrugh killed Casper, Frank is his father, Dixon was following Woodrugh because he suspected as much, the Mayor doesn't trust Velcoro nor care about him and tried to have Velcoro, Bezzerides, and Woodrugh all killed by the Mexicans, Woodrugh wants to expose the corruption in Vinci, take down his father Frank, and expose corruption in big business like the Catalyst group who are related to Black Mountain.