The executions are carried out at dawn on Haqlania Bridge, the entrance to Haditha. A small crowd usually turns up to watch even though the killings are filmed and made available on DVD in the market the same afternoon.
One of last week's victims was a young man in a black tracksuit. Like the others he was left on his belly by the blue iron railings at the bridge's southern end. His severed head rested on his back, facing Baghdad.
Children cheered when they heard that the next day's spectacle would be a double bill: two decapitations. A man named Watban and his brother had been found guilty of spying.
With so many alleged US agents dying here Haqlania Bridge was renamed "Agents' bridge." Then a local wag dubbed it "Agents' fridge," evoking a mortuary, and that name has stuck.
A three-day visit by a reporter for the Guardian last week established what neither the Iraqi government nor the US military has admitted: Haditha, a farming town of 90,000 people by the Euphrates river, is an insurgent citadel.
That Islamist guerrillas were active in the area was no secret but only now has the extent of their control been revealed -- they run Haditha's security, administration and communications.
A three-hour drive north from Baghdad, under the nose of a US base, Haditha is a miniature Taliban-like state. Insurgents decide who lives and dies, which salaries get paid, what people wear, what they watch and listen to.
Haditha exposes the limitations of the Iraqi state and US power.
For politicians and diplomats in Baghdad's fortified Green Zone the constitution is a means to stabilize Iraq and woo Sunni Arabs away from the rebellion. For Haditha, 225km northwest of the capital, whether a draft is agreed is irrelevant. Residents already have a set of laws and rules promulgated by insurgents.
Within minutes of driving into town the reporter was stopped by a group of men and informed about rule No.1: announce yourself.
The mujahidin must know who comes and goes. The reporter, who for security reasons has not used his real name, did not say he worked for a British newspaper. For their own protection interviewees cannot be named.
There is no fighting here because there is no one to challenge the Islamists. The police station and municipal offices were destroyed last year and US Marines make only fleeting visits every few months.
Two groups share power. Ansar al-Sunna is a largely home-grown organization, though its leader in Haditha is said to be foreign. Al-Qaeda in Iraq, known locally by its old name Tawhid al-Jihad, is led by the Jordanian-born Abu Musab al-Zarqawi. There was a rumor that Zarqawi, Washington's most wanted militant after Osama bin Laden, visited early last week. True or not, residents wanted to believe they had hosted such a celebrity.
A year ago Haditha was just another sleepy town in western Anbar Province, deep in the Sunni triangle and suspicious of the Shiite-led government in Baghdad but no insurgent hotbed.
Then, say residents, arrived mostly Shiite police with heavyhanded behavior.
"That's how it began," one man said.
Attacks against the police escalated until they fled, creating a vacuum filled by insurgents.
Alcohol and music deemed unIslamic were banned, women were told to wear headscarves and relations between the sexes were closely monitored. The mobile-phone network was shut down but insurgents retained their walkie-talkies and satellite phones. Right-hand lanes are reserved for their vehicles.