Islamic State in Iraq and the Levant (ISIL) militants publicly executed eight Sunni men in a small northern Iraqi village at the weekend for allegedly plotting against the group, an eyewitness from the village told Reuters on Sunday.

The killing began on Friday night when a pair of masked ISIL gunmen openly murdered a police officer in al-Jumasah village after the militant group accused him of spying for the Kurdish and Iraqi military forces, the witness said.

ISIL fighters gathered local residents to watch the execution in the village, about 120 kilometers (75 miles) north of Tikrit.

“ISIL members said that this is the fate of anyone who opposes them,” the witness said. “They presented as evidence CDs and copies of the man’s correspondences with the security forces.”

After the police officer was executed, a small armed group opened fire in revenge on the house of an ISIL officer.

On Saturday morning, the witness said, 10 ISIL cars drove around al-Jumasah with two masked informants, who helped the fighters identify 10 people they suspected of attacking their member’s house the previous night.

That evening, three were released and seven others — all but one relatives of the slain policeman — were executed.

ISIL, which seized much of northern Iraq in June, controls large parts of Salahuddin, Nineveh, Diyala and Anbar provinces, often in collaboration with smaller armed groups, and has declared an Islamic Caliphate in Iraq and Syria.

New Prime Minister Haider al-Abadi hopes to convince Iraq’s Sunni minority to rebel against ISIL, but many remain deeply suspicious of the country’s ruling Shiite elite.

Hopes of a Sunni revolt are also complicated by the ruthlessness of ISIL, which has intimidated, imprisoned or killed those who reject them in Sunni communities.