The 45 members were put alive in morgue freezer in Mozul and were left for 24 hours to a slow death, American Herald Tribune reports.
The frozen bodies of the executed were later put at the entrance of the city.
The executed members were believed to be fled the confrontation that were taking place with Iraqi forces in Heet district.
Earlier in February 2015, ISIS burned 45 Iraqis to death in al-Baghdadi. During the same time, ISIS also broadcast the video of a young Jordanian pilot being burned alive in front of a cheerful crowd.
“These terrorist groups have desecrated all human values. They have committed the most heinous criminal terrorist acts against the Iraqi people whether Shi’ite, Sunni, Christians, Turkmen, Shabak or Yazidis,”United Nations Ambassador Muhammed Ali Al-hakim told to media.
UN committee on the Rights of the Child alleges that ISIS are using Iraqi boys aged under 18 as suicide bombers, bomb makers and human shields. ISIS are also selling abducted children as sex slaves.