ABOARD A US MILITARY AIRCRAFT: The US soldier suspected of killing 16 Afghan civilians in a shooting rampage could face the death penalty if convicted, US Defence Secretary Leon Panetta said Monday.

The Pentagon chief told reporters aboard his plane  enroute to Kyrgyzstan that the suspect in the Afghan shooting spree would be brought to justice under the US military legal code, which allows for the death penalty in some cases.

Asked if the suspect could be sentenced to death, Panetta said, “My understanding is in these instances that could be a consideration.” Despite demands from the Afghan parliament for a public trial, Panetta's remarks echoed earlier statements from Washington that the rogue soldier would be tried in a US military court.

After walking off his base, the suspect entered Afghan homes and fired on civilian families, “then at some point after that came back to the forward operating base and basically turned himself in. Told individuals what happened,” Panetta said.

When asked if that amounted to a confession, Panetta said: “I suspect that was the case.”Panetta condemned the incident as a “terrible loss of life” and said it remained unclear what may have led the gunman to murder civilians, pending the outcome of a US investigation.

“We're not sure why, what the reasons were,” he said. “I have assured President (Hamid) Karzai that he will be brought to justice and held accountable.”