Prisoners has been in suspended development for several years, and has juggled actors and directors; reported names have included Leonardo DiCaprio and directors Antoine Fuqua and Denis Villeneuve. New word is that an offer has been made for the role of the lead—a father who kidnaps and tortures the man he believes responsible for the abduction of his young daughter—to Michael Fassbender.
Fassbender has sprung to the foreground of the movies world with impressive force. His supporting roles in 300, Inglourious Basterds and Jane Eyre, and his costarring role in X-Men: First Class, have demonstrated the actor's versatility. If he can handle an Ancient Greek warrior, an undercover WWII soldier who stays sophisticated even in the face of imminent death, and a mutant-gone-bad, I think vigilante father is well within his range.
There is much we have yet to learn about the man who is power-jogging into the spotlight at gazellian speed, but "Under the Radar" seems to have a pretty good lock on this champion.
There is no word on any additional casting for the film.