Two gunmen attacked a Texas event promoting lampoons of the Muslim prophet Muhammad on Sunday, wounding a security officer before being shot to death by authorities. One of the men was described as an American convert to Islam and a "wannabe" jihadist. The pair was believed to have been targeting the American Freedom Defense Initiative, an organization known for incendiary statements about Muslims that describes itself as dedicated to free speech. Below are some other examples of how depictions of Muhammad have led to violence, and why images of him are considered so offensive.
Why is depicting Muhammad in cartoons considered so offensive?
For centuries, Muslims have been discouraged or banned from depicting Muhammad, the most highly revered human figure in Islam, in images and other forms.
The images that do exist of Muhammad often block his face, says Akbar Ahmed, a former Pakistani ambassador to the United Kingdom and now chair of the Islamic Studies department at American University in Washington, D.C.
For the record, May 5, 3:11 p.m.: An earlier version of this post misspelled Akbar Ahmed's name as Akabar Ahmed.
Although depicting Muhammad is not specifically prohibited by the Koran, Islamic law bars the practice, and the vast majority of Muslims believe they should avoid depicting Muhammad out of respect for him, Ahmed says.
The texts are open to interpretation and there are some drawings, particularly in Iran, where the prophet and other religious figures are fully depicted, with their faces uncovered, Ahmed says.
Because of this near-universal ban, some Muslims have become particularly sensitive about any portrayals of Muhammad, let alone those that could be seen as insulting.
“When he’s depicted in a very deliberately provocative or insulting manner, as a terrorist, for example, then of course as you can imagine it upsets Muslims even more,” Ahmed says. “It’s a question of their very identity, for Muslims.”
Still, Ahmed says, only a small minority of Muslims would resort to violence to defend Muhammad's name. In a statement after the Texas shooting, the Council on American-Islamic Relations condemned the attack, calling it "more insulting to our faith than any cartoon, however defamatory."
Why does Islam prohibit images portraying the prophet Muhammad?
The ban on images of Muhammad is tied to an Islamic edict against worshiping idols, experts say.
“The idea is if you have an image of the prophet, tomorrow you’ll want to put a picture or a drawing of the prophet in your home or office, maybe the next day, you’ll want a statue, and the next step might be worshiping the statue,” says Ahmed. “The argument is it is a slippery slope, and it’s best not to have images at all.”
How has the prophet Muhammad been portrayed in the past?
Drawings often show him with a white light covering his face, Ahmed says. Literature describes Muhammad as well-built, with a beard and long hair, he adds.
In the 1977 film "The Message," which was about Muhammad's life, filmmakers put the character off camera or behind the lens, and placed a disclaimer at the beginning explaining that the prophet would not appear.
How have images of Muhammad incited violence in recent years?
In January, two armed men stormed the offices of the French satirical magazine Charlie Hebdo, shooting to death 12 people, including eight journalists.
The magazine has been known to lampoon Muhammad on its cover and in its pages, depicting him in irreverent, and sometimes offensive, cartoons. The killers, French-born Said and Cherif Kouachi, claimed they were “avenging the prophet” as they fled the scene.
Stephane Charbonnier, also known as Charb, is shown with the front page of Charlie Hebdo in this September 2012 photograph. Charbonnier was among those killed in the shooting at the magazine's offices in January. (Associated Press)
Two separate standoffs with police left the two shooters, as well as another gunman, Amedy Coulibaly, and four other people dead. Coulibaly had been named a suspect in the killing of a female police officer near Paris.
In 2012, the 14-minute film “Innocence of Muslims” prompted violent protest throughout the Islamic world.
The low-budget film, posted on YouTube, portrayed Muhammad as a womanizer and a pedophile.
The film was blamed for subsequent attacks on U.S. missions in Egypt, Yemen and Libya, the latter of which resulted in the death of the U.S. ambassador to Libya, J. Christopher Stevens, and three other embassy workers.
An armed man gestures as buildings and cars are engulfed in flames inside the U.S. consulate compound in Benghazi, Libya, in 2012. (AFP/Getty Images)
A Danish newspaper published a series of cartoons ridiculing Muhammad in 2005. After the cartoons were reprinted in a number of European newspapers, violent protests erupted in Syria, Afghanistan, Lebanon and other parts of the Muslim world.
And in 2004, Dutch filmmaker Theo van Gogh was assassinated by Mohammed Bouyeri, the leader of a group of Dutch-born Islamic militants, after he made a film critical of Islamic society.
Ahmed says many Muslims feel the effect of such events is cumulative, and outrage is building. “The feeling is growing in the Muslim world that this is cumulative, and it’s deliberate,” Ahmed says of offensive depictions of Muhammad. “There’s one, and then another, and then another. This figure, who is central to Islam, is being insulted repeatedly and it feels to them like deliberate provocation.”
What are some examples of how fear of Islamic backlash has altered decisions about depicting Muhammad?
In 2006, following the fervent protests after the Danish cartoon publications, the German Opera in Berlin decided not to revive a production of Mozart’s “Idomeneo,” which contained a scene showing the severed heads of Poseidon, Jesus, Buddha and Muhammad.
Comedy Central refused to air a 2010 episode of “South Park” after the show’s creators received death threats from an Islamic extremist website that referred to Van Gogh's 2004 slaying. The episode depicted Muhammad in a bear suit, but the network chose instead to cover the character with a block that said “censored” and bleeped audio referring to Muhammad. The show’s creators later said executives made the decision without their approval.
Reacting to the network’s decision and to the death threats that "South Park'" creators had received, Seattle-based artist Molly Norris drew a cartoon showing various objects -- including a cup of coffee, a tomato and a box of pasta -- all claiming to be the likeness of Muhammad. At the top of the illustration, she christened May 20, 2010, as “Everybody Draw Mohammed Day.”
“Do your part to both water down the pool of targets and, oh yeah, defend a little something our country is famous for ... the first amendment,” she wrote. The image went viral, and Norris received numerous death threats. She later said she had a change of heart, as did Jon Wellington, who had set up a Facebook page dedicated to the day. The threats prompted Norris to change her name and move, and she has been in hiding since.
A 2010 “Non Sequitur” cartoon strip was pulled by several newspapers, including the Los Angeles Times. The cartoon presented a scene that imitated the “Where’s Waldo?” children’s books by asking “Where’s Muhammad?” amid a drawing of a grassy park with animals, children and adults at play.
The catch: Muhammad did not appear in the drawing.
Ahmed says he believes the conflicts over publishing images of Muhammad are bound to continue.
“We have been seeing this clash of two civilizations for decades. On the one hand, you have Western civilizations upholding the ideals of a free press, which I believe must be upheld. And then you have the Muslim world, which believes this is a deliberate insult on their most sacred [human] figure in their faith.” For more breaking news, follow me @cmaiduc on Twitter.