Supposedly, the most-common advice given to screenwriters in present day Hollywood is: Don't specialize. Be good at something, fine, but get your name on as much of "everything else" as possible. Make sure they know you're available for action, comedy, scifi, whatever.
David Ayer's career stands out like a living rebuke to that advice - since 2000, Ayer has written (and more-recently directed) eight films: "U-571," "Training Day," "The Fast & The Furious," "Dark Blue," "S.W.A.T," "Harsh Times," "Street Kings" and now "End of Watch." Of those eight, seven are crime-action/dramas and all but one of them center on embattled, ethically-compromised LAPD cops.
His new joint, "End of Watch," stars Jake Gyllenhaal and Michael Pena as two cops who get into a protracted scuffle with Cartel-backed LA drug gangs; the "hook" this time being that a supposedly-significant amount of the action is presented "found footage" style from security cameras and the cops' own dashboard-cam. A new red-band trailer has just been released: