Los Angeles: History is littered with murderers inspired by art: Charles Manson believed the lyrics to the Beatles' "Helter Skelter" were a prophecy that ignited a killing spree. John Lennon assassin Mark David Chapman was obsessed with the book Catcher in the Rye.
For Anders Behring Breivik, like Columbine High School shooter Eric Harris, it was video games.
Breivik revealed to an Oslo court on Thursday that the popular military game Call of Duty: Modern Warfare and the online role-playing game World of Warcraft helped condition him for his bombing and shooting rampage that left 77 people dead last summer in Oslo and at a Labor Party youth camp on Utoya island.
Video games have come under scrutiny before, as when Columbine High School shooter Eric Harris avidly tinkered with the first-person shooter Doom. Activision Blizzard Inc., maker of Call of Duty and World of Warcraft - two of the world's most popular video games - did not immediately comment on Bleivik's statement that the games helped him train.
Video game companies have long argued that their games are forms of entertainment that are no different than movies or television. And fans of each of those genres have taken their obsessions to a different level by mimicking what they've learned for real-life nightmares.
Here are five examples of media over the past 40 years that have sparked terrifying atrocities:
Call of Duty: Modern Warfare: Breivik testified Thursday that he prepared for his attacks with this popular first-person shooter created by Activision Inc. developer Infinity Ward. He said he used the shoot-'em-up war simulator to practice "target acquisition" with the game's virtual holographic rifle sight, a type of laser used to aim at foes.
The Sopranos: After being arrested for the murder of their mother, Jason Bautista and his half-brother told police in 2003 that the idea to chop off her head and hands to hide the crime was lifted from an episode of the HBO mobster drama in which Tony Soprano kills an associate and has his head and hands removed before the body is dumped.
The Secret Agent: Federal authorities said in 1996 that "Unabomber" Ted Kaczynski was inspired by the 1907 novel by Joseph Conrad that features a mad professor who abandons academia in disgust to live in isolation and build a bomb. They believed he used variations on Conrad's name as an alias when checking into hotels in Sacramento.
Natural Born Killers: The 1994 movie starring Woody Harrelson and Juliette Lewis as star-crossed killers has been linked to more than a dozen slayings, including the 1995 robbery-murder spree of Benjamin Darras and Sarah Edmondson that led to one of the victims filing a lawsuit that blamed the filmmakers for the crime spree. It was dismissed in 2001.
Magnum Force: Dale Selby Pierre and William Andrews testified in court that they came up with the idea to quickly and efficiently kill hostages by making them ingest drain cleaner during their 1974 robbery-rape-murder dubbed the "hi-fi murders" from this 1973 thriller starring Clint Eastwood. In the film, a prostitute is forced to drink drain cleaner.