Military investigators suspect that the US soldier charged with premeditated murder over the killings of 17 Afghan civilians committed the shootings in two separate operations, The New York Times reported Sunday.
Citing an unnamed US official, the newspaper said the investigators believed that the soldier, Staff Sergeant Robert Bales, left his base and carried out the first set of killings, returned to the combat outpost and then, sometime later that evening, went out and attacked a second village.
It was on his return from the second outing that Bales was detained, the report said.
The official said this account emerged from a range of interviews that army investigators conducted over the last several days as they tried to piece together what happened that night and why, according to the paper.
Bales was charged Friday with 17 premeditated murders as well as six counts of assault and attempted murder in the Panjwai district of Kandahar province on March 11.
The killings -- mostly of women and children -- are believed to be the deadliest war crime by a NATO soldier during the decade-long conflict and have tested an already tense relationship between Washington and Kabul to the limit.
Bales, 38, is currently being held at Fort Leavenworth in Kansas, and a US forces spokesman said it was "more than likely" the trial would be held in the United States, although the decision is still pending.
Furious relatives of the victims have demanded that proceedings take place in Afghanistan.