Faruq Mohammed al-Zarzour “was threatened by some groups in authority and armed men of the region,” an intelligence source from Mosul told Rudaw.
Al-Wataniya List is led by Ayad Allawi, a former prime minister and current president of Iraq.
The source, who spoke on the condition of anonymity, said Zarzour was killed in his own home by “unidentified armed men.”
The perpetrators are at large.
ISIS issued a claim of responsibility on Monday.
Zarzour, who holds a doctorate in agriculture, appeared in a video recently predicting that his list would gain six seats in Nineveh province.
“Al-Wataniya alliance will gain six seats in Nineveh and my morale is high and the success is near,” he said.
Addressing his enemies and adversaries, he said, “Do not threaten. Come and let’s arrange debates and TV interviews.”
ISIS has threatened to carry out attacks on candidates and polling stations.
Iraqis go to the polls to elect a new parliament on May 12.
