Gunmen shouting "God is Great!" dragged the burning body of what they said was a U.S. pilot in a horrific video posted Wednesday on the Web by a new Al Qaeda-affiliated group that claimed it shot down an Apache helicopter last weekend.

On Thursday the U.S. military said Iraqi forces have captured the prime suspect in last year's kidnapping of Italian journalist Giuliana Sgrena.

Mohammed Hila Hammad Obeidi, also known as Abu Ayman, was arrested in southern Baghdad on March 7 but the announcement was delayed pending DNA tests to verify his identity, the U.S. command said in a statement.

Abu Ayman is believed to have led the Secret Islamic Army in Babil province south of Baghdad and is said to have close ties to Abu Musab al-Zarqawi, head of Al Qaeda in Iraq. He was also an aide to the chief of staff of intelligence during Saddam Hussein's regime, the U.S. statement said.

Also Thursday, roadside bombings in Iraq killed two security forces and wounded at least 12, officials said.

One of the bombs exploded near a police patrol in western Baghdad, killing a policeman and wounding five, officials said. A second bomb detonated when another group of police arrived at the scene, wounding two more policemen.

North of the capital, an Iraqi army patrol was also hit by a roadside bomb, killing one officer and wounding five soldiers outside the city of Baqouba.

Meanwhile Wednesday, the U.S. military expressed outrage over the release of "such a despicable video for public exposure" but said it had serious doubts that the footage was authentic.

The AH-64D Apache Longbow attack helicopter was downed near Youssifiyah about 12 miles southwest of Baghdad on Saturday, killing the two pilots. A U.S. statement said troops had recovered "all available remains" although "reports of a Web site video suggest that terrorists removed part of a body from the crash site."

The flaming wreckage of a helicopter could be seen clearly in the video, including outlines of the aircraft's blades and jagged pieces of wreckage strewn over a field.

The camera panned over bloodstained debris, then showed several men dragging the burning body of a man across a field as they shouted "Allahu Akbar," or "God is Great!" Voices could be heard in the background shouting "come, come, help me carry it."

The body's face was not visible, but the camera zoomed in on what appeared to be his waistline, which showed a scrap of underwear with the brand name "Hanes." It appeared the man was wearing tattered digital camouflage fatigues, which are worn by U.S. troops in Iraq.

The time stamp on the video which shows the minutes and seconds do not run sequentially, and the scenes appear disjointed. The posting also included bombing scenes filmed elsewhere, indicating the material had been edited as a propaganda package.

Lt. Col. Barry Johnson, a spokesman for the command, said the wreckage shown on the video "does appear to be an AH-64" but added that other helicopters of that type have been lost.

"We have serious doubts about the authenticity of this video, a common tactic we see terrorist groups use to keep the stories they want alive in the media," he said.

But in Alexandria, Va., Ben Venzke, head of IntelCenter, a defense contractor which monitors militant statements, said it appeared on first viewing that the tape was authentic. Although the date stamp on the video was Sunday, April 2, a day after the crash, Venzke said the discrepancy could be simply a technical error in the setting.

"Based on an initial review of the footage, it would seem to indicate the downing of a helicopter and the removal of crew and passengers from the craft," he said. "On an initial review, it does appear to be what it purports to be."

He said the large amount of background chatter among those on the ground suggested that "it was filmed closely after the downing of the helicopter as opposed to something that was found later and staged."

It was the second Apache to crash in Iraq this year. On Jan 16, an AH-64 Apache conducting a combat air patrol went down in Mishada, north of Baghdad, killing two soldiers. At least 12 Apaches have crashed since the beginning of the war three years ago.

U.S. officials first reported Saturday that an American helicopter had crashed that day about 5:30 p.m. during a combat patrol southwest of the capital and that the status of the crew was unknown. Ordinarily, U.S. officials refrain from reporting helicopter crashes until the status of the crew is clear to avoid tipping off the insurgents that wounded survivors may be in the area.

Late the next day, the U.S. command confirmed that helicopter was an Apache and that the two crew members were "presumed dead," suggesting the remains had not been found. Later the same day, U.S. authorities said the bodies had been recovered.

On Wednesday, the military identified the pilots killed as Capt. Timothy J. Moshier, 25, of Albany, N.Y., and Chief Warrant Officer 3 Michael L. Hartwick, of Orrick, Mo.

The video was e-mailed to reporters and posted on an Islamist Web site by the Mujahedeen Shura Council, purportedly a new umbrella organization that includes Al Qaeda in Iraq and smaller insurgent groups. Formation of the group, announced Jan. 21, was seen as a bid to consolidate various organizations that had been operating independently since the insurgency erupted in 2003.

It was also seen as an effort by insurgents to lower the profile of Al Qaeda in Iraq leader Abu Musab al-Zarqawi, a Jordanian, whose mass attacks against Shiite civilians have tarnished the image of the insurgents among many Iraqis.

"We are outraged that anyone would create and publish such a despicable video for public exposure," Lt. Col. Jonathan Withington, a U.S. spokesman, said. "The terrorists continue to demonstrate their immoral disregard for human dignity and life."