DIWANIYA - Eight hundred Iraqi soldiers were divided into lines of ten men, given rushed interrogations by Islamic State fighters and shot dead, the survivor said. By dawn, he was one of only 20 left alive.
Mohammed Majul Hamoud, a 24-year-old survivor who spoke to Reuters in his home town of Diwaniya, south of Baghdad, said he was spared because he pretended to be a Sunni Muslim Bedouin.
In the worst known massacre during Islamic State's war, Hamoud was held by the militants for 11 days in June and recounted their systematic killings in chilling detail.
He belonged to a group of 1,500 soldiers fresh from basic training. As word came of Islamic State's advance, the group was sent to Camp Speicher near Tikrit city.
Having trouble breathing from his beatings, Hamoud spoke of betrayal by his own commanders at Speicher, who he said had promised recruits like himself safe passage out when Islamic State took Tikrit yet allowed them to be led to their deaths.
"We were sold and deceived," Hamoud said. Hamoud and his comrades had no rifles or pistols and found that the armory at Speicher was empty.
The senior commander for the province, General Ali al-Freiji, told the soldiers a deal had been reached with local tribes to allow the units to leave, according to Hamoud and two other soldiers.
Government officials deny this. They say there was no promise of safe passage, and the unarmed recruits left the safety of the base despite having been ordered to stay.
Freiji departed and the next day, Sunni tribesmen entered the base to escort them out. Most soldiers were afraid to go, Hamoud said.
"The tribes assured us we are under their protection, and that we are going to Samarra." LIE FACE DOWN Outside the base, they filed into a long line. They marched on the main highway towards Tikrit.
But they knew they had been deceived when they reached the city's university. Their tribal escort ordered them to lie face down and they were handcuffed, Hamoud said.
"Anyone who moved or raised his head was shot." From the ground, Hamoud saw a woman approach, and he hoped she was going to shame the gunmen standing over them. Instead she encouraged him.
"She told a tribesman 'I know you are a good man, good Muslim and courageous. I ask you not to leave all these Shi'ite dogs alive, kill them all' and she kissed his head." Hamoud saw children gathering near the long line of men, cars stopping to gawk, and people cheered at the sight of the captured soldiers.
Hatred for the Shi'ite-led government and the army had grown in neglected Sunni majority cities like Tikrit.
The gunmen went up to each prisoner and took their shoes, socks, rings, wallets and identity cards. Anyone hiding a valuable was shot. They executed a man lying next to Hamoud, who tried to conceal a ring.
Locals rounded up soldiers who had tried to hide in the area.
The soldiers were handed over to Islamic State fighters who marched them 20 miles to former President Saddam Hussein's old palace grounds, where they were blindfolded and executed.
Islamic State, which posted video and photographs of the graves on the Internet, said it killed 1,700 prisoners. Human Rights Watch says it has documented the deaths of between 560 and 770 soldiers, and believes the real toll is higher.
"We were more than 800 in a big hall. We had no water, no food. They poured a bottle of water over us and laughed when some opened their mouths to get a drop." IS fighters assembled the prisoners in groups of 10. Interrogators asked them their ranks and the names of their units.
"They handcuffed and blindfolded the ones they were taking and gave them some water to drink. Then we heard 'God is Great' and shooting." Hamoud's group included his brother Kamil and four cousins. When it was Hamoud's turn to stand up and be taken for execution, he spoke in a Bedouin accent.
He said: "Can you spare a drink of water." They asked where he was from. He lied and told them he belonged to the Shummar, a large tribe with both Sunnis and Shi'ites, and came from Baiji, a Sunni town to the north.
They removed him from the line as his brother and cousins were taken outside where other soldiers had been executed.
"They handcuffed and blindfolded me and let me sit down," Hamoud said.
He had no time to dwell on his brother, he said, but now holds out a faint hope for his survival.
"There is a chance," he said, praying that his brother and cousins escaped.
The shooting stopped at around dawn and Hamoud saw that the room that had been filled with hundreds now had only 20.
A man with a Saudi accent began to interrogate Hamoud and the others to determine if they were really Sunni Muslims.
Hamoud had invented a fake name for himself, Bandar, to hide from them that he was a Shi'ite. He avoided praying, explaining as a Bedouin he was not in the habit.
Under rapid-fire questioning, those believed to be lying were summarily shot. Hamoud's group shrunk to 11.
After a few days, a missile hit the compound. The chandelier in the room shattered and two men tried to escape. Hamoud loosened his handcuffs and watched from the window as the two soldiers were gunned down. He retightened his handcuffs.
Finally on his 10th day in captivity, an IS fighter said they were being freed.
One of his guards told him, "You, the Bedouin: tell your people we don't harm the Sunnis, and that we were giving you good food, water and everything you need." The next day, six of them were escorted to a house, where a final investigative committee interrogated him.
"They asked me if I performed daily prayer. I said no. One of them told us: 'take him and teach him how to pray'. They dragged me as I was too weak to walk and started to beat me." His group of 11 were driven to a nearby checkpoint and given a number to ring if they were stopped at any Islamic State checkpoint.
The terrified group went to a nearby village, where one of the men had friends.
They stayed at a farm house and his fellow soldiers contacted their families, but Hamoud was afraid of what the other soldiers, who were Sunnis, would do if they discovered he was a Shi'ite.
They knew him as Bandar and he suspected they wondered why he hadn't called his relatives. He overheard the owner of the farm talking about him to the others. The farmer said: "I think Bandar is a Shi'ite and not Sunni but by God I will protect him more than I protect my sons." The next day, Hamoud confessed his faith, and the farmer assured him he was safe. Hamoud called his father, who asked to speak to the farmer.
The farmer said: "I will protect him and consider him as one of my sons."