By Lisa Richwine
LOS ANGELES (Reuters) - The release of Warner Bros.' movie "The Dark Knight Rises" brings to an end one of Hollywood's most enduring franchises, as the studio searches to find a new one capable of matching Batman's box office success.
Forecasts for opening weekend ticket sales were thrown into doubt after a shooting in Colorado on Friday at a midnight screening of the film. Twelve people were killed.
Warner Bros. said in a statement that the studio was "deeply saddened" by the incident and extended sympathy to the families of the victims.
New York City planned to deploy police officers at screenings of the film, and theaters nationwide began reviewing and tightening security.
Hollywood box office watchers said the movie industry had never faced a situation like this. "This is a tragic and unprecedented event," said Paul Dergarabedian, box office watcher for Hollywood.com.
The Time Warner-owned studio has been Hollywood's King of Franchises for years. Over the last decade it generated worldwide ticket sales of $12 billion from its "Lord of the Rings," "Batman," and "Harry Potter" films.
Eight of the 20 highest-grossing films of all time come from one of those franchises, according to website Box Office Mojo.
"The Dark Knight Rises" will be the last of the Batman series that began in 2005, director Christopher Nolan said.
"Harry Potter," Warner Bros.'s biggest franchise, ended last summer with the largest of eight films, "Harry Potter and the Deathly Hallows - Part 2," which generated $1.3 billion worldwide.
Franchise films are especially important to studios because they use the big-budget movies to ramp up revenue by creating theme park rides and TV shows and selling toys and memorabilia.
Warner Bros. is counting on a pair of "Hobbit" movies to rekindle the magic of "Lord of the Rings." The first installment is due in December.
A reboot of the "Superman" franchise is also scheduled for next summer with "Man of Steel," made by "Dark Knight" producer Legendary Pictures. Nolan, one of Hollywood's hottest directors, is a producer on that movie.
The films could pave the way for Warner to unite Batman, Superman and other characters from its DC Comics stable in a "Justice League" movie, said Gitesh Pandya, editor of website Box Office Guru.
That would follow the strategy that brought staggering success to Walt Disney Co with "The Avengers," a movie that brought together a handful of Marvel superheroes and generated nearly $1.5 billion in worldwide sales.
One problem for Warner Bros. is that not every DC Comics character has been a phenomenal hit, Pandya said.
Last summer's "Green Lantern" did not work very well, he said, grossing $219.8 million. Some industry watchers said the movie cost $200 million to produce, though Warner has disputed that figure. Studios receive about half of box office sales.
The 2006 "Superman Returns" also disappointed, Pandya said.
The aim is to create another series like Batman, which won critical acclaim, fan devotion and $1.4 billion in ticket sales for "Batman Begins" in 2005 and 2008's "The Dark Knight."
"The Dark Knight" grabbed $158 million in the United States and Canada on its opening weekend in 2008, a record at the time and still the highest debut for a movie that was not boosted by higher-priced 3D tickets.
Opening weekend ticket sales for "Dark Knight Rises," which cost $250 million to produce, had been expected to at least match the last Batman film, according to box office forecasters, and possibly reach as high as $198 million, just shy of the $207 million record set by "Avengers" in May, some industry analysts said.
Beyond superheroes and the "Hobbit," Warner intends to bring "The Hangover 3" to theaters next summer, the next installment in the adult comedy series that has grossed $1 billion.
(Reporting by Lisa Richwine; Editing by Ronald Grover, Michael Perry and Bernadette Baum)