According to a report in The Times of London, investigators say American troops removed bullets from the bodies of the victims, which included two pregnant women, a teenage girl, a police officer and his brother.
The soldiers then cleaned the wounds with alcohol before telling their commanders the civilians had been discovered already dead for many hours, according to the Afghans, who spoke to The Times on condition of anonymity.
NATO has confirmed that the five residents of Khataba village were killed erroneously in the nighttime raid on Feb. 12, when a joint force of U.S. and Afghan Special Forces stormed their home after a tip suggested a Taliban militant was hiding there.
"Despite earlier reports we have determined that the women were accidentally killed as a result of the joint force firing at the men," NATO spokesman Lieutenant-Colonel Todd Breasseale told The Times. The Western military alliance denied the claims that there had been any cover-up.
The Afghan government's investigation into the raid is ongoing, and officials involved in the probe would not go on the record for The Times story, saying they had to wait until the results were made public.
NATO vowed a full investigation into the civilian deaths immediately following the incident, according to the British newspaper, but later said it had been made impossible by the victim's prompt burial in accordance with Muslim tradition.