Even though Denzel Washington, Rami Malek and Jared Leto are big stars, they never stop worrying about the little things. The three teamed up in a new psychological thriller that poses serious acting challenges — even for a trio of titans who have all won Oscars. In “The Little Things,” they portray complex characters with cryptic back stories or mysterious motivations in the film about detectives working to track down a serial killer in Los Angeles during the early 1990s. Director John Lee Hancock aimed to flip the crime genre on its head, and introduced flawed characters such as Washington’s...