BAGHDAD - The video posted last night showing the beheading of the American hostage Eugene Armstrong is the latest example of the ruthlessness of the Iraqi militant group responsible.
Six months ago, Tawhid and Jihad (Unification and Holy War) was just one of numerous militant groups operating in the chaos of Iraq. But in recent weeks, as the insurgency has spiralled out of control, the group has established itself as the most sophisticated and brutal in the country.
Mr Armstrong and his colleagues Jack Hensley and Briton Kenneth Bigley were seized last week in a carefully planned operation that had all the hallmarks of Tawhid and Jihad. The three westerners had been living in an anonymous two-story house in Mansour, an affluent suburb of Baghdad which is home to foreign embassies and Iraqi politicians.
Gunmen from the group had clearly been tipped off about the men. On Thursday morning, they pulled up outside the house in an unmarked minivan and another car. At 6 am, the power in the street failed, and two of the westerners wandered out of their unguarded compound to start their generator. The gunmen grabbed them, bundled all three into their minivan and drove off.
By the time the Iraqi police arrived at 7am they had vanished, possibly into a safe house in Baghdad, but more probably to Falluja, the centre of Iraq's flourishing kidnapping industry and a stronghold of Iraq's resistance.
The US claims that Tawhid and Jihad is masterminded by Abu Musab al-Zarqawi, the Jordanian militant apparently responsible for numerous terrorist and suicide attacks in Iraq. It also claims that Mr Zarqawi is allied to al-Qaida.
Such links have not been proven. But there is little doubt that Tawhid and Jihad includes not just Iraqi insurgents but foreign Arab fighters, who have flooded into Falluja since the US withdrew from the town in April after a three-week siege.
Iraq's resistance currently appears to be split into two main camps - old-fashioned Iraqi nationalists who are concentrating their efforts on fighting Americans and dislike the idea of killing fellow Iraqis; and newer, more radical groups such as Tawhid and Jihad who believe in targeting anyone who collaborates with the US occupation, including the Iraqi police, government officials and provincial governors.
The second group appears to be better funded. It is more organised. It has superior intelligence. It is more professional. And it is more deadly.
Its uncompromising message also appears to be gaining in popularity - at least among Iraqis already hostile to the Americans and Iraq's interim government. When insurgents destroyed an American Bradley fighting vehicle in Baghdad's Haifa Street, the scene of heavy fighting this month between US forces and Sunni militants, they placed the black flag of Tawhid and Jihad in the vehicle's smouldering gun barrel.
Last night's video showed Mr Armstrong in an orange jumpsuit - worn by prisoners held by the Bush administration in Guantánamo Bay. The symbolism is not a coincidence.
The group's demand that all female Iraqi prisoners be freed from US jails in Iraq appears to be not a real demand but an attempt to exploit an issue that has incensed ordinary Iraqis.
The US has already released all but two female prisoners from its jails in Iraq but it continues to hold around 5,000 male detainees in Abu Ghraib and Umm Qasr, a US prison near British-occupied Basra. Few of the prisoners have been charged; all of them have been locked up without trial, some for more than a year.
Many of the detainees are from Iraq's Sunni heartland where support for groups such as Tawhid and Jihad is growing.
Hope for Mr Bigley and Mr Hensley has been fading. Their only chance of escape is if the American authorities receive a last-minute tip-off as to where they are being held - highly unlikely in a shadowy world where anyone suspected of being an American spy suffers the same gruesome fate as the western hostages.
One of the best-selling CDs in Baghdad's market shows an Egyptian accused of working for the Americans having his head sawn off in a scruffy backyard.
The CD is professionally produced, using the latest technology.
These are grim times for Iraq, and for the few remaining westerners in Baghdad.
© 2004 Guardian Newspapers Ltd.