Read the New York Times article that this story comes from here. And the relevant paragraphs are right here:

In interviews on Monday, five of Mr. Hashemy’s neighbors, four of whom said they saw part of the attack, provided an account. From 20 to 25 men uniformed men arrived in about eight sport utility vehicles. They surprised his guards and chased him onto the roof, and then to the roof of a neighbor, Abu Amar, residents said. It was there that the attackers shot him in the head, the witnesses said. The men then seized two neighbors, their children, one of their wives and an elderly man, a baker, all of whom witnessed the attack. The men sounded like they were speaking Arabic with a foreign accent, residents said. After they took Mr. Hashemi’s guards, one was heard shouting to another, “go, go,” in English.

If it's true that the people who executed the Iraqi Vice President's brother were speaking English, that obviously has tremendous implications. Who were they? And what were their motives?