Video Length: 31:53

Driving at night, on a road in northern Iraq where insurgents often attack, a Kurdish government official is headed for a clandestine meeting. Dr. Mohammed Ihsan is investigating the disappearance more than 20 years ago -- during the early years of Saddam Hussein?s brutal dictatorship -- of 8,000 Kurdish men and boys. ?This case is particularly significant,? says FRONTLINE/World reporter Gwynne Roberts . ?Their abduction marks the point when Saddam?s regime moved from isolated acts of brutality to mass murder.?

The case Dr. Ihsan is putting together will become a vital part of the indictment against Saddam at his trial in Baghdad.

Ihsan is meeting a former Iraqi secret policeman a few miles from the oil city of Kirkuk. Spotting a car waiting by the side of the road, Ihsan pulls up behind the vehicle and jumps out to collect a handful of documents -- more evidence he needs in order to unravel the mystery of the missing Kurds.

Back in his office, Ihsan, who is the minister for human rights in the regional government of Iraqi Kurdistan, shows Roberts an official document he has uncovered that says the missing Kurds were executed in August 1983 in the town of Bussia, near the border with Saudi Arabia. But he needs proof.

Before beginning his journey to the remote desert town, Ihsan visits a mountain village where Kurdish women covered in black are still mourning the loss of their husbands, fathers, brothers and sons. Their suffering and continuing uncertainty about what happened to their loved ones is the driving force behind Ihsan?s investigation. His search is authorized by Masoud Barzani, a clan leader and now president of the Kurdish region of Iraq. Barzani has a personal motivation: He says he lost 37 members of his own family. Moreover, it was Barzani?s decision to side with Iran against Iraq during the Iran-Iraq war in the early 1980s that provoked Saddam?s wrath. The dictator took his revenge on Barzani Kurd civilians living in government camps.

Ihsan shows Roberts an eerie September 1983 black and white videotape in which Saddam summons Kurds to hear him denounce the ?treachery? of the Barzanis. ?They?ve been severely punished and have gone to hell,? Saddam declares. A captive audience obediently applauds. The abduction of the Barzani Kurds was the precursor to Saddam?s infamous Anfal campaign, in which his forces used terror tactics, including poisonous gas, to kill more than 100,000 Kurdish men, women and children.

Ihsan?s expedition gets under way from Arbil, a relatively peaceful and prosperous Kurdish city in northern Iraq. But even here, there is danger. In a bloody, chaotic scene, a suicide bomber kills 70 and injures 120 in a line of young Kurds waiting to join the police.

The Kurdish team of investigators, accompanied by Roberts and his video crew, finally make their way to Baghdad, where insurgent attacks are at a record high. They stay at the Babylon Hotel, outside the heavily fortified Green Zone where the Iraqi government and the U.S. Embassy are hunkered down. Worried about the safety of his team, Ihsan puts his brother, Azad, in charge of security. Azad explains to the hotel staff that he will have to shoot anyone who comes to their floor after midnight. ?I gotta kill ?em,? he emphasizes. ?No excuses.?

From their base at the hotel, Ihsan?s team makes forays into Baghdad to track down government documents that were looted after the defeat of Saddam?s regime in 2003. Amazingly, they are for sale in various cluttered ?document shops.? In the markets, they also find videotapes showing the old Ba?ath regime torturing and murdering prisoners. Once more, Ihsan obtains an important document -- this one a 1987 letter from Saddam?s secretary to Ali Hassan al-Majid, aka ?Chemical Ali,? notorious for using poisonous gas against Kurdish civilians. The document says, ?No one knows the fate of these families [the Barzani Kurds] except the leadership of the State.?

Pressing on into the southern desert, Ihsan?s convoy weaves its way through territory controlled by al-Qaeda terrorists. ?They prey on traffic jams,? notes Roberts, ?and Dr. Ihsan orders his drivers not to stop at any cost.? The convoy also tries to steer clear of U.S. military vehicles and fears that it may come under ?friendly fire? from U.S. Apache helicopters overhead.

At last, nearly 300 miles southwest of Baghdad, they reach a remote desert fortress, an abandoned prison, Nugra Salman, which once held political prisoners, including the Barzani Kurds. A few who survived their incarceration recall the torture and death of their fellow inmates. ?I often asked God to take my soul,? says one old man. ?I begged God to put an end to my life.?

Ultimately, Ihsan?s team arrives in Sunni-dominated Bussia, where Ihsan hopes to find witnesses who will lead him to the graves in which the bodies of executed Kurds are buried.

There is deep distrust here between the majority Sunnis and the minority Shi?iahs. The Shi?iah prove helpful. Ihsan finds two important sources among them -- a shepherd who confirms that the Kurds were executed and a shopkeeper who says a security officer in charge of the Kurdish prisoners barged into his store demanding the kind of cloth used for burial shrouds.

But the Sunnis, who were closely allied with Saddam?s regime, are closed-mouthed. Ihsan arranges a meeting with the town?s Sunni elders and offers them money as a reward for information. He peels off hundred-dollar bills to pay those who provide assistance. ?Will money break their silence?? Roberts wonders.

The next day, two shady-looking characters, Sunni bounty hunters, come forward to claim their share of the reward, leading Ihsan to a Bedouin camp in the blistering desert where they say they believe the Barzani Kurds were executed and buried. Ihsan orders his bulldozers to begin excavating, but they find nothing. Another informant sends Ihsan and his men deeper into the forbidding desert. Again they dig, again they are frustrated. The process continues for 15 days until they begin to run out of food, water and hope.

At the same time, they get word that insurgents are circling the area, monitoring their movements and waiting for an opportunity to attack. Reluctantly, Ihsan orders his team to suspend operations and withdraw to the north. It appears that his investigation, which began 14 years ago, will fail.

?But five months later, Dr. Ihsan is called back to Bussia,? reports Roberts, ?after his Shi?iah contacts finally locate three mass graves, just a few hundred feet from where he?d searched in May. The remains of 500 Kurds are recovered, all of them believed to be Barzanis.?

In a stark and unforgettable scene, Ihsan and his team unearth the skeletal remains of the Kurdish men and boys, holding up blindfolded skulls and bits of traditional Barzani Kurdish cloth. This forensic evidence will be used by prosecutors in Saddam?s trial. It is a heart-wrenching discovery, and for Dr. Ihsan, it confirms the worst about Saddam and the Iraqis who supported him.

?Forget it,? he says. ?I personally don?t think there is any hope that we can live together.?