It was originally thought that 190 troops were slaughtered when the terror group overran and conquered Saddam Hussein's hometown. But crucial satellite imagery uncovered three new execution sites and tripled the death toll.

These photographs, footage of the gruesome massacre and harrowing eyewitness accounts have now helped convict 24 of the ISIS fanatics behind the atrocity.

An Iraqi court has sentenced them to hang for their role in the slaughter of hundreds of soldiers on Wednesday. Four others were acquitted for lack of evidence and as many as 604 other militants, who are also thought to have taken part, are still at large.

The day after conquering the city in central Iraq, ISIS claimed it executed 1,700 Shi'ite 'members of the army' who were trying to escape the coming onslaught.

The terror group began to release gruesome videos and images which showed the men shackled together and shot in the head - before their bloodied corpses were thrown into shallow trenches.

All of the defendants pleaded not guilty and claimed they did not take part part in the massacre - insisting their confessions were coerced under torture by Iraqi officers.

Several relatives of the deceased soldiers stormed the courtroom and threw shoes and water bottles at the defendants while they were being questioned by the chief judge, the Guardian reports.

Some of them burst into tears when the sentences were passed, before raising pictures of their relatives and chanting: 'Allahu Akbar.' 

After analysing the horrendous imagery, Human Rights Watch (HRW) said two trenches were located in a field 100m away from the 'Water Palace' - which can be seen on the overhead images. 

But a newly-released ISIS propaganda video of the execution and satellite imagery helped identify three new execution sites - elevating the death toll by between 285 and 440 to up to 770.

The largest of the three new sites is located on the north side of the Saladdin al-Ayubi building which lies within the presidential palace's compound, where as many as 440 men were slaughtered

They were gunned down on either June 12 or 13 at around 9.30am, video images cross-referenced with satellite imagery indicates.

The bodies seem to have disappeared on satellite images shot a few days later on June 16, but blood stains can be seen on the concrete. They also revealed bulldozers and other earth-shifting vehicles in a dirt field nearby. 

This linked up with an ISIS propaganda video which showed ISIS militants using a bulldozer to cover the bodies with soil after each round of execution, before unloading the next group of men at the site.

The second new execution site was found at the 'Water Police' building next to the Route 24 bridge, while footage of the execution showed ISIS fighters executing between 25 and 30 men at this site using handguns.

The murdered around 30 men at around 6.30pm on June 12, before dumping their bodies in the nearby Tigris River.

A 23-year-old who incredibly survived the mass-slaughter described how he was captured with thousands of other men as they sought to flee the area.

Ali Hussein Kadhim, a Shi'ite Iraqi soldier, was lined up for execution by the ISIS firing squad while his Sunni colleagues were spared death.

After shooting three of his fellow soldiers in the back of the head, the assassin turned his gun on Kadhim and missed by millimeters.

He instinctively fell forwards into an open grave dug for the victims of the murderous rampage - a decision that would save his life.

Kadhim told HRW how ISIS fighters stripped them of their mobile phones and money when they first seized them on June 12 - before driving them to what he described as a palace.

There he was cruelly crammed into a shipping container with 100 other detainees for six hours. Two men died due to the overcrowding and blistering heat.

Islamic State militants took them out of the container at around 5pm, broke them up into smaller groups and took each one to a different location. 

Kadhim said he was in a group with nine other men, and heard the sound of gunfire from other execution sites, including the nearby Water Police building. 

Their Islamic State captors bound his and other prisoners' hands behind their backs and covered their eyes, then forced them to crouch forward with each man holding the t-shirt of the man in front between his teeth as they marched them to the bank of the Tigris. 

They then lined up the ten men and shot them with a pistol, one after another. Ali said that beneath his blindfold he saw the man next to him fall to the ground covered in blood, but that somehow he was not hit, so he fell to the ground and feigned death until nightfall, when he escaped under cover of darkness.

(dailymail.co.uk)