By Barbara Starr and Chris Lawrence, CNN
(CNN) - The military is investigating whether alcohol was a factor in the weekend shootings allegedly committed by a U.S. soldier in two villages in Afghanistan, two senior military officials told CNN Tuesday.
One of the senior military officials said alcohol was found on the base in the area where the suspect lived. It is not clear yet if the alcohol belonged to the soldier; a toxic screening was conducted but the results have not been returned, the official said.
The military has presented a determination of "probable cause" to allow it to hold the Army staff sergeant suspected in the shootings, which occurred in two Afghan villages, an International Security Assistance Force official told CNN. Under the rules of military justice, a probable cause finding is necessary within 48 hours after the suspect is taken into custody to show there is a enough evidence to continue detention.
Military investigators are continuing to sort through the events of this weekend as they prepare a case against the suspect.
The military is reviewing imagery showing the soldier leaving and returning to the base, the officials said. The base had what is known as persistent surveillance for perimeter security. There is no imagery from the villages.
Investigators from the Army Criminal Investigations Division, the lead agency on the case, are interviewing a "range of individuals both on the American and Afghan side," including members of the alleged shooter's team, Pentagon spokesman Capt. John Kirby said Tuesday.
A U.S. official familiar with some elements of the investigation said the investigators have "recovered some initial evidence" from the scene, including shell casings. American soldiers typically carry the M-4 carbine rifle, which uses high-powered rounds and can be used in a semi-automatic mode for repeat firing.
Because the victims are believed to have been shot at close range in their homes, it's likely many of the high-powered bullets went completely through the bodies and landed in the walls.
"Ballistics is not going to be a problem," the official told CNN.
While officials are likely to be able to recover much of this material, all the victims have been buried and permission to exhume the bodies is unlikely, the official said.
After the investigation ends, the findings will be sent up the chain of command, and military officials "will then make judicial process decisions," according to Kirby. He said it's too soon to know whether the soldier will be tried in Afghanistan.
Two U.S. officials said there is no deadline for making the charges public. In many cases charges come within two weeks of initial detention.
The military will not release the suspect's name until charges are formally made, or "preferred," by military authorities.
For now, the plan is to keep the suspect in Kandahar, where the investigators working in the area can easily get access to him.
Gen. John Allen, the commander of all U.S. and NATO troops in Afghanistan, has yet to decide when and how the man will be moved back to the United States. It is likely he will be moved back to the United States at some point because the legal proceedings are likely to extend beyond his tour of duty in Afghanistan.
President Barack Obama referred to the actions as murder in comments made Tuesday about the shooting, but White House spokesman Jay Carney said the president was not making a legal judgment.
"What I've made (known) to President (Hamid) Karzai when I spoke to him is that the United States takes this as seriously as if it was our own citizens and our own children who were murdered," Obama said in a statement from the Rose Garden.
"I think ... innocent Afghan civilians were killed," Carney said when White House reporters asked about the president's word choice. "How that happened and why that happened is under investigation. So I wouldn't go beyond that, and I think that he was not going beyond that."
The military is trying to clamp down on release of information because of growing concerns that leaks and public statement could be used by a defense attorney to claim the suspect could not get a fair trial, military sources said.
Carney also said the president did not imply there was more than one shooter when he said, "We'll follow the facts wherever they lead us and we will make sure that anybody who was involved is held fully accountable with the full force of the law."
"My understanding," Carney explained, "is there's no reason to believe that there was more than one shooter, but that they are talking to a number of individuals as part of that investigation."
Allen told CNN's Wolf Blitzer on Monday that investigators believed the shootings were "the actions of a single soldier."
"The evidence at this point, both in terms of observations and reports and interviews, lead us to believe that he acted as an individual at this point," the general said in an interview broadcast on "Situation Room."
The secretary of defense suggested to reporters traveling overseas with him that the death penalty is a possibility in the case.
"My understanding is that in these instances that could be a consideration," Panetta said.
No service member has been put to death since 1961, though a number have been sentenced to death and are on death row.
President George W. Bush was the last to authorize the death penalty for a soldier, which he did in 2008 for a service member whose crimes were committed in the 1980s. Should the suspect in the Afghanistan shooting be found guilty and sentenced to death, it will likely be up to a future president to approve the sentence.
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