The Arabic-language al-Sumaria news website quoted an informed source as saying that the terrorists killed the people for cooperating with and spying for the Iraqi security forces.
The source, who spoke on condition of anonymity, said Daesh (ISIS / ISIL) terrorists tied the people with rope and put them in a large basin containing nitric acid.
The source further added that the execution was performed in public to scare other people.
On May 13, ISIS terrorists also executed 11 residents of Mosul on charges of using mobile phones.
ISIS terrorists burned the entire five members of an Iraqi family alive in Kirkuk city on May 10 after accusing them of trying to escape terrorist-held territories.
In late April, ISIS members also executed 250 women in Mosul after the victims did not accept a proposal to temporarily marry the militants.
Earlier this month, United Nations Special Representative for Iraq and Head of the United Nations Assistance Mission for Iraq (UNAMI) Jan Kubis told the UN Security Council that over the recent months, more than 50 mass graves have been found in various parts of Iraq that were previously controlled by ISIS.
Iraqi security forces and medical staff collect the remains of people killed by the Daesh terrorist group from a mass grave on January 26, 2016, a day after it was found in the al-Jamiya area of central Ramadi. (AFP photo)
Gruesome violence has plagued the northern and western parts of Iraq ever since ISIS terrorists launched an offensive in June 2014 and took control of portions of Iraqi territory.
The militants have been committing heinous crimes against all ethnic and religious communities in Iraq, including Shias, Sunnis, Kurds, Christians and others.
S/SH 11