The military did not disclose the victim's nationality, but Houston-based KBR confirmed he was one of its employees.

Reporting from Baghdad and Kirkuk, Iraq - A U.S. soldier was arrested in connection with the fatal shooting Sunday of a civilian contractor on an American military base in the northern Iraqi city of Tikrit, the military said.

The shooting occurred at 8:30 a.m. and the civilian died of his wounds later in the day.

"We can confirm that a soldier has been identified and detained in the alleged shooting incident of a civilian contractor here on Contingency Operating Base Speicher," U.S. military spokesman Maj. Derrick Cheng said in an e-mail.

The military did not release the nationality of the victim. However, Houston-based KBR confirmed in an e-mailed statement that he was one of its employees, 27-year-old Lucas Vinson.

"As the Army is leading the investigation of the incident, KBR is not providing further comment at this time," spokeswoman Heather Browne said in the statement. "We are of course fully cooperating with the Army on its continued investigation."

Elsewhere in northern Iraq, a Kurdish woman and her three children were found shot to death in their home Sunday morning in Banja, a small community just north of Kirkuk. It was unclear whether the shootings were linked to criminal activity or to the region's Arab-Kurdish tensions. Police said the children were 6, 4 and 2, and the assailant had shot them with a 9-millimeter pistol. The two older children were girls and the youngest a boy, according to police.

A neighbor, Mohammed Qadir, said he had called the police because he was nervous for the members of the family after they had been left alone by the woman's husband, a policeman, who had to work overnight.

The husband sat crying in front of his home Sunday. He said he had arrived back from work in the morning shortly before the police arrived and discovered the bodies.

"I was astonished when I found my family, my wife and three children were killed while they were in their bed," said Amid Abdul Rahman, who fell silent for a minute. Then he waved his hand and shouted: "Oh my God, may you take revenge on the killers. . . . What is the guilt of my son Mohammed and he is an infant! What is the guilt of my small daughters?"

Meanwhile, violence rocked the northern city of Mosul. A bombing targeted a police commander's convoy and left a pair of his bodyguards wounded, police said. Two people were wounded in an explosion outside a hospital, while in a third blast, two more civilians were wounded, police said.

ned.parker@latimes.com

Windawi is a special correspondent. Special correspondent Omar Hayali and Times staff writers Caesar Ahmed and Raheem Salman contributed to this report.

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