The Islamic State of Iraq and Syria (ISIS) executed as many as 190 captives earlier this month, according to Human Rights Watch.
Their report is based on an analysis of satellite imagery and graphic photos released by ISIS terrorists.
"The number of victims may well be much higher, but the difficulty of locating bodies and accessing the area has prevented a full investigation," the rights group said.
The news comes as thousands of Iraqi Christians are fleeing for their lives this week before the brutal onslaught of the jihadist army.
ISIS terror groups are still attacking Christian villages as they press on in their attempt to take more territory.
'They've Cut Off Heads'
At a checkpoint near the Kurdish controlled areas, both Christians and Shiite Muslims warned of an ongoing slaughter at the hands of ISIS.
"They (ISIS) have cut off heads. There are eight bodies on the riverbanks. No one knows what they want," Iraqi refugee Ahmed Hussein said.
Approximately 2,000 Christians sought refuge in the Kurdish city of Erbil after Sunni Muslim gunmen attacked their towns near the city of Mosul.
Iraqi Christian refugee Ibrahim Marzina says he hopes to leave Iraq.
"There are a lot of people who wish to emigrate in this situation because our future is unknown," he explained. "And in general, the future of Iraq is unknown. But we as a Christian minority, our future is even more unknown. Honestly, we can't predict our future."
It's a familiar refrain for the Christians who are left in Iraq. Hundreds of thousands have fled the country since the U.S. ousted Saddam Hussein 11 years ago.
"We won't have a future here in Iraq—never. Now I want to emigrate to a European country. Now. At this moment," Iman Abdul Azis Majid, another Christian refugee, said.
Fellow refugee Abdul Wahed Abd al Boules echoed those sentiments.
"Yes, we are afraid for Christians (in Iraq). Different groups of Christians are treated badly. They're being displaced," he said.
One group of refugees is now living in a sports center. Others have been sent to nearby schools, suffering from lack of sleep and exposure to hot weather.
With no one to defend them, the situation for Christians is likely to get more desperate.
"The only protected zones for the Christians are within the Kurdistan Region Government territories, especially within the Kurdish territory in Iraq," Ano Jawhar Abdoka, the head of Shlama Entity for Christians Issues, explained.
"Other places are very dangerous," he continued. "And there are very (many) tensions, of violence against the Christians all over Iraq, especially in the middle and the south of Iraq."
As the U.S. struggles to find a diplomatic solution to the unraveling situation in Iraq, the chances are good that thousands more refugees will join those already in the Kurdish-controlled areas of the country's north.