Death penalty possible in Afghan killings case, AP reports

Defense Secretary Leon Panetta said the death penalty could be possible as the military investigates a U.S. soldier suspected of shooting and killing at least 16 Afghans on Sunday, according to the Associated Press. Speaking to reporters traveling with him to Kyrgyzstan on Monday, Panetta said the killings must not derail the U.S.-led military mission in Afghanistan.

Meanwhile, Reuters cites a U.S. official as saying the Army staff sergeant was treated for a traumatic brain injury sustained in 2010 in Iraq. The official, however, did not say there was necessarily a link between that injury and the killing spree in Afghanistan.

Gen. John Allen, commander of the U.S.-led coalition in Afghanistan, told CNN earlier on Monday that the suspect acted alone. The soldier, who was supporting a village stability operation to help local police, was quickly noticed when he left his base in the Panjwai district in southern Afghanistan. As the American soldiers realized who was missing during a headcount, and the search party was forming, Allen said, "we began having indications of the outcome of his departure."

Although Allen would not release the suspect's name to protect the investigation, he did confirm that the soldier served three tours in Iraq before deploying to Afghanistan.

Allen offered his "sincere condolences" to the victims, their families, and the Afghan people. "We are investigating it aggressively, and we will hold the individual accountable should the evidence point to his culpability here," Allen said.

Allen's command will take the lead in the investigation. Amid calls from some Afghan officials to take charge of the investigation, Allen promised that the U.S. would keep the Afghan government informed throughout the investigation and potential prosecution. "But this individual will be investigated, and the outcome will be in accordance with U.S. law."