Army experts continued Wednesday to scour a dark, grainy video of an execution for clues about the identity of the victim, his captors and other useful information.

The Arab satellite station Al-Jazeera (search) reported Monday that the man being shot in the head was Spc. Matt Maupin (search), 20, of Batavia, Ohio, but Department of Defense officials still say they can't be sure.

"Every effort possible has been made for further analysis of the tape," said Brig. Gen. Michael Beasley, who visited the Maupin home Wednesday along with U.S. Rep. Rob Portman (search), R-Ohio. "The status of the information known today remains the status. The tape is entirely inconclusive."

Lt. Col. Pamela Hart, an Army spokeswoman, said officials usually won't make a final determination that a soldier has died until remains are recovered.

With this video and others from war zones, the Army uses intelligence sources, audio- and image-enhancing tools and cultural details, such as tribal patterns in cloth, to help their analysis.

"Some (agencies) would be reviewing the video to determine the identity of the person or persons within the video. Other agencies would be determining whether they can get any intelligence out of that video or determine perhaps the location where it was filmed," said Lt. Cmdr. Nick Balice at U.S. Central Command in Tampa, Fla.

Army technicians are searching the video like a puzzle, looking for any clues that can help: They examine the clothing worn, any scars or birthmarks, jewelry, the weather, time of day, and structure or room where it was filmed.

They also listen to the voices, dialect and exterior sound. Experts can use digital and audio enhancement tools to try to match the voices on the video to the voices of Iraqi insurgents they already have on tape.

It was that kind of audio analysis that helped U.S. intelligence officials determine "with high probability" that terrorist Abu Musab al-Zarqawi (search) was the masked man who beheaded American civilian Nicholas Berg in a video that circulated on the Internet in early May.

Experts also are using information gathered by different agencies about Iraqi insurgents and other terrorists in the Middle East to identify the captors.

"Sometimes, if you have multiple, different pieces, they all come together to paint a more complete picture," Balice said.

In the video released by Al-Jazeera on Monday, a blindfolded man, whom his captors identify as Maupin, is shown sitting on the ground. It was taped from behind a man whose face does not appear in the video.

The station says that in the next scene, gunmen shoot the man in the back of the head, in front of a hole dug in the ground. The station did not broadcast the killing.

Maupin, who is listed by the military as captured, was taken captive after his convoy was attacked April 9 west of Baghdad. A week later, Al-Jazeera broadcast a videotape showing the soldier sitting on the floor surrounded by five masked men holding automatic rifles.