They're meant to be shocking, and they are. The decapitation murders of hostages in Iraq and Saudi Arabia represent an escalation of tactics by Al Qaeda-linked groups in their campaign to sow fear and helplessness among their opponents.
But it may be important to remember that the motivation for these brutal acts is modern. There is nothing Islamic, or traditionally Middle Eastern, about beheadings, say experts. Instead, they represent another adaptation by a cruelly imaginative terrorist movement, the next new thing from people who pioneered the use of hijacked airliners as weapons.
"There's nothing particularly religious about this," says Asma Afsaruddin, associate professor of Arabic and Islamic studies at the University of Notre Dame. "It's absolutely morally reprehensible."
It's true that Saudi Arabia employs public decapitation as its means of capital punishment. Last year the Saudis executed 53 criminals convicted of everything from murder to lesser crimes such as drug offenses. And Islamist terrorists have employed the technique in the recent past. Chechen rebels have videotaped some beheadings. During Algeria's long war against French occupation, one Muslim rebel leader even wrote a pamphlet trying to justify his group's use of beheadings in religious terms.
But throughout history many cultures have employed decapitations as punishment at one point or another. The wives of Henry VIII and Marie Antoinette were among past famous victims.
More recently, the Japanese subjected some prisoners to beheading during World War II, though the extent of Japan's use of the practice remains unclear. France last used the guillotine in 1977.
While Al Qaeda and its allies may claim religious justification for their actions, there is nothing in the Koran justifying beheadings. Indeed, there is nothing in the literature of mainstream Islam that justifies the killing of innocents in any form, say experts.
The Council on American-Islamic Relations, based in Washington, has called the recent trend of brutal violence "senseless." A statement from the group says it repudiates "all those who believe such murderous behavior benefits the faith of Islam or the Muslim people."
In South Korea on Wednesday, people reacted with shock and horror to the beheading of translator Kim Sun Il, whose body was found by a US patrol between Baghdad and Fallujah. President Roh Moo-hyun called it a "crime against humanity," and said he would proceed with plans to dispatch 3,000 South Korean troops to Iraq by August.
An Al Qaeda-linked group headed by the Jordanian-born terrorist Abu Musab al-Zarqawi claimed credit for the murder. Video of Kim had shown him dressed in an orange jumpsuit, kneeling in front of a black banner emblazoned with the Zarqawi group's name and emblem. US warplanes fired missiles at what officials described as a known Zarqawi safe house in Fallujah on Tuesday night. But an audiotape alleged to be of Mr. Zarqawi's voice surfaced on an Islamic web site on Wednesday.
The voice on the tape threatened Iraq's interim prime minister, Iyad Allawi, with assassination. The speaker said "we will not get bored" and will continue efforts to kill the Iraqi leader until he meets the same fate as Izzadine Saleem, the Iraqi Governing Council president killed last month in a car-bombing claimed by Zarqawi's group.
The voice on the tape vowed to fight as long as necessary. "We will carry on our jihad against the Western infidel and the Arab apostate until Islamic rule is back on earth," the voice said.
The horrible stagecraft involved in the Kim murder, and in the previous similar killings of businessman Nicholas Berg in Iraq and military contractor Paul Johnson in Saudi Arabia, maximized the terror effect on outside audiences, note terrorism experts.
The orange jumpsuits worn by some of the victims emphasized the prison-like atmosphere, and perhaps were an intentional echo of the Abu Ghraib prison and US abuses carried out there on Iraqi prisoners. The lengthy buildup to the actual murder, with preliminary videos, long statements, and threats, only heightened the sense of dread the terrorists wished to convey.
Referring in particular to the killing of Mr. Johnson in Saudi Arabia, a country where security forces were actively seeking his kidnappers, former CIA official Stanley Bedlington says the group involved has demonstrated its capabilities. "It takes some organization, knowledge, and skill to pull this off," he says. "They have no defectors among their ranks, no leaks, no forms of communication that are intercepted."
The series of recent murders has captured attention in the rest of the world in a way the car bombings and other attacks have not. In that sense, it is likely to happen again. "This is an attention-getting maneuver, and it seems to be working," says Afsaruddin.