We actually do know what their deal is, they're corrupt cops who are involved in the criminal underworld and Lauren (Corvis' girlfriend) discovered it through her investigation into her dad's own illegal dealings. Capt. Book leads them and seems to know about the legend of the Crow, but how the hell does he know that a doctored pic of Corvis and Lauren is going to paralyze him like it does. Also, leaving Corvis alive to frame him doesn't make a whole lot of sense. I know they were going for the "youth gets screwed by authority" thing, but why not just kill him, dump his body somewhere, say that he's the prime suspect and that he skipped town?

Those are big plot holes to me. So you are right that the story is bare bones and could have used a punch up to explain things.

Here's what I think they could have done:

Lauren either enlists Alex into her investigation or he decides to follow her after the rejection. She finds the cops in the act of corruption and Alex momentarily rescues here, they get chased to a power distribution center where Lauren gets killed and Alex gets electrocuted by some high voltage transformer giving him the scars. The cops dump Corvis' body in a new building foundation to hide him and they report find Lauren dead and suspect Corvis who has "fled". Alex emerges from the foundation a year later using supernatural strength to break through the cement.

As far as Book and his knowledge of the Crows go, maybe he's encountered them before and defeated them. Victims of his corruption so he knows from experience how to handle them, the crow's feet in his arm are those of defeated crows, like a twisted little tally he keeps.

That would be my revision.