Gunmen killed a Sunni Arab village chief and his three sons when they burst into his home just south of Baghdad on Wednesday before fleeing, Iraqi security and medical officials said.
Just after midnight, the armed men entered the home of Mohammed Dwaiyeh, the chief of Albu Osaj village, and gunned down him and three of his sons and wounded another, an interior ministry official said.
The son who was hurt was a fighter in the anti-Qaeda militia known as the Sahwa, the official said. The Sahwa sided with the US military against Al-Qaeda from late-2006 onwards, helping turn the tide of the insurgency.
A medic at Yarmuk hospital in Baghdad confirmed the facility received the four bodies, and said they had been sent on to the city morgue.
Albu Osaj lies near the town of Lataifiyah, in a confessionally mixed region south of the capital known as the Triangle of Death for the high levels of violence there in 2006 and 2007.
Though violence is down markedly from its peak during those years, attacks are still common, and more than 200 people have been killed in the month since US forces completed their withdrawal from Iraq.