LONDON – Last month the world learned about the brutal murder of an extraordinary Iraqi Shiite cleric who had just returned from exile with the help of U.S. troops.

I have sought more details about this killing because they reveal so much about contemporary Iraqi society – and even about this past week’s wave of Mideast suicide bombers. So I stopped in London, on my way to Baghdad, to talk with a cleric who was with Sayyid Abdul Majid al-Khoei when he was slain.

The story he told holds chilling implications for American interests in the Middle East.

The 40-year-old Khoei had hoped to promote tolerance in Iraq and act as a bridge between the United States and the Shia religious community. Instead, he was hacked and shot to death near the sacred Shia shrine of Imam Ali in Najaf. This apparent assassination came at the behest of a thuggish young cleric, Muqtada al-Sadr, who has risen to prominence in the wake of the Iraq war. It reflects the brutalization of Iraqi youth under Saddam.

Shaikh Salah Bilal, in white turban and tan robe, still takes deep pauses as he recalls 90 minutes of horror leading up to the murder. Khoei had wanted to promote reconciliation between Shia factions, so he brought with him to the shrine its unpopular custodian, who had been close to the Saddam government. Some say the custodian was the target of the murderers, but Bilal insists that the real target of the killers was Khoei.

At first the crowd welcomed Khoei, and called out the name of his late, famous father whose religious standing as an ayatollah was the highest in Shia Islam. But then a group of young clerics started chanting, “Yes, yes to al-Sadr,” and things got tense. Bilal never believed these clerics would contemplate the murder of a devout Muslim and son of such a famous family, in which two brothers were murdered by Saddam: “There was no way that could happen.”

But suddenly, bullets shattered the window of the custodian’s office. A visiting Iraqi-American cleric from Detroit was hit. Two of Khoei’s fingers were blown off.

Khoei had told the Americans he didn’t need security, but now he sent emissaries to the U.S. base for help. It didn’t arrive. After 90 minutes of shooting, al-Khoei sent someone out with a white T-shirt and a Koran to surrender. Nine young clerics with some gunmen entered and demanded, “Where is Sayyid Majid al-Khoei?”

“They said they wanted to take him to Muqtada al-Sadr,” Bilal recalled with a shudder. “They tied our hands in back and forced Sayyid Majid to take off his bulletproof vest.” The custodian was dragged away and murdered, and Khoei was repeatedly stabbed with knives and swords.

Bilal and the bloodied Khoei were flung in front of the nearby door of al-Sadr’s home, which the clerics then entered. When Bilal begged them to save his friend, they slapped his face. After three minutes, the group emerged and announced their leader’s verdict: “Sayyid Sadr said, “Move them away from my door.”‘

Bilal and Khoei then staggered into a nearby sewing machine shop, but the young clerics dragged Khoei away. Bilal later learned that he was dragged through the streets for half a mile, alive, and then was finally shot.

The message of this tragedy goes beyond the irreparable loss of the moderate Khoei. The fact that youthful clerics would murder an ayatollah’s pious son reveals the rage and brutalization of a sizeable segment of Iraqi youth.

Jordanian political analyst Labib Kamhawi expanded on this point: “The regime of Saddam Hussein forced people to lose their self-esteem. They have no standards to fall back on. This is a different era from the time of ayatollah Khoei, when there was respect for the clergy and for scholarship and educated people.”

“The time when we grew up,” says the fortysomething Bilal, “was a time of different teaching, life, schools. Under Saddam, the teaching was different. These youths had no scholarship. Under Saddam, this became a killing society.”

So in Iraq, young Sadr, whose ayatollah father was murdered by Saddam, can himself call on young clerics to kill. The slums of Baghdad are filled with unemployed, angry Shia youth who suffered under Saddam and are receptive to such a call. Meantime, in many Arab countries where secular politics are discredited and job prospects slim, support for religious extremists provides an outlet for youthful rage.

The Sadriyoun (Sadr’s band) don’t yet dominate Iraqi slums and could be undercut if the society and the economy rejuvenate fast. But if the U.S. occupation drags on, the young and violent are bound to turn on Americans. One cleric’s death could become a preview of something much worse.

Trudy Rubin is a columnist and editorial-board member for the Philadelphia Inquirer.