The first thing you’ll want to know about “Alex Cross” is: Can Tyler Perry carry it off? The answer is: Sort of, but not really.As novelist James Patterson’s beloved Washington-based detective and Sherlock Holmesian forensic psychologist, Perry has a tall order to fill. Not only must he banish all thoughts of Morgan Freeman, who previously portrayed the character in “Kiss the Girls” (1997) and “Along Came a Spider” (2001), but he must also shake his association with Madea, the over-the-top drag role for which Perry is best known.To assist with the first part, director Rob Cohen -€ along with writers Marc Moss, who penned “Spider,” and Kerry Williamson -re-situate the action in Detroit, not DC, turning it into a prequel of sorts to the two earlier films. It’s like a superhero origin story.That analogy is oddly apt. Over the course of “Alex Cross”, which follows the detective’s pursuit of a psychopathic assassin (Matthew Fox) who has killed Cross’ wife (Carmen Ejogo), our hero turns into a morally dubious avenging angel. Forget about Morgan Freeman; Perry’s more like the Punisher from Marvel Comics, bending and in some cases breaking the rules to exact his single-minded revenge.As for Madea, Perry does his darnedest to maintain a poker face, and he largely succeeds. He’s a fungible action hero, interchangeable with almost any other when it comes to running, jumping, punching and shooting. When it comes to the hard work of acting, however, he’s lacking, most notably in scenes surrounding and following his wife’s murder. Fake grief just doesn’t suit him.Perry is moderately better at conveying smouldering rage, which he shares with his cop partner (Edward Burns), whose girlfriend and fellow officer (Rachel Nichols) has also been murdered, in grisly fashion. Although rated PG-13, “Alex Cross” is surprisingly violent, and includes images of torture.This, of course, is because “Alex Cross” is less of a Tyler Perry movie than a Rob Cohen movie. The director of “The Fast and the Furious” and “XXX” leaves his bloody prints all over the place, indelibly. Freeman would likely not have fared much better than Perry does here, considering the unsubtle material that the movie’s cast has to work with.Fortunately, some of the film’s tone of strained seriousness is cut by moments of genuine humour, even if some of it is unintentional. Early in the film, when Cross tells his wife that he’s considering moving to Washington to take a new job as an FBI profiler -€ sequel alert -€ she replies: “I have no idea what the public schools are like in D.C.” That line got an appreciative chuckle from a preview crowd.In the role of Cross’ opposite, Fox makes the strongest impression. Known as “the Butcher of Sligo,” his villain may be generic € he’s a nut who considerately leaves clues at the crime scene -€ but the actor is so physically transformed that fans of “Lost” may hardly recognise him, with his shaved head and sinewy physique. The cat-and-mouse game that his character plays with Cross is enjoyable enough, even if the twist tacked on at the end disappoints.But “Alex Cross” isn’t meant to be analysed too deeply. The title character probably sums up the best strategy for appreciating the film’s modest pleasures when he says, “Don’t overthink it; I’m just looking for a bad guy.”Alex Cross (PG-13) is showing at the Liberty Theatre