Tom Hanks' Dr. Robert Langdon character now needs to crack another mystery -- who will direct the next Dan Brown adaptation, "The Lost Symbol."

Ron Howard, who directed and produced both 2006's "The Da Vinci Code" and 2009's "Angels & Demons" will not be directing the next movie based on Brown's 2009 bestseller, according to Deadline.com.

With Hanks on board for the film, Sony Pictures is currently looking for a new director, after Howard declined to return for a third film. It seems to be as surefire a hit as a movie could be, considering that "The Lost Symbol" a million copies on its first day and became the fastest-selling adult novel ever.

Instead, Howard (whose most recent non-brown movies have been box office underperformers "Missing," "Cinderella Man" and "The Dilemma"), will focus on two projects at Warner Bros. The first is an adaptation author Jon Krakauer's real-life religious thriller "Under The Banner Of Heaven," the second is a live-action take of Mad magazine's beloved comic strip "Spy vs. Spy."

Howard's ambitious "The Dark Tower," a three-film/two-TV series adaptation of Stephen King's sprawling fantasy epic, was recently stalled at Universal after years of development in various forms. It's unlikely that that project will be resurrected anytime soon.

Meanwhile, Hanks can be seen opposite Julia Roberts in "Larry Crowne" (which he also directed) and will soon star in "Extremely Loud and Incredibly Close" with Sandra Bullock.