Doctors Without Borders said the revised death toll from the strike was arrived at after an exhaustive investigation by the organization that included combing through the rubble of the hospital to find further human remains, interviewing family members of missing victims and crosschecking with other hospitals. The group said it concluded that the death toll was “at least 42 people”: 14 staff members, 24 patients and four relatives of patients.

“Although determining the death toll has been extremely difficult in the chaos of the facility’s wreckage following the attack, extensive efforts have been undertaken to identify those who have died,” the group’s statement said. “As well, additional human remains had been found in the hospital rubble over the course of the past two months.”

The United States military conceded, after an internal investigation, that the Oct. 3 airstrikes on the hospital were a mistake. It blamed human error and mechanical and systems failures, and it said that action would be taken against an unspecified number of American servicemen. However, the military did not release the report of the investigation, and so far there has been no announcement of what disciplinary or other actions, if any, have been being taken against those deemed culpable.

Doctors Without Borders has demanded an international investigation of the airstrikes that would be carried out under the Geneva Conventions, asserting that the military’s own investigation would inevitably be biased and lack credibility. But such an investigation could only take place if both Afghanistan and the United States consented to it.

Senior Afghan officials have continued to insist, in the absence of any credible evidence and even in contradiction of the United States military’s findings, that the hospital had been used by the Taliban during the fighting. The United States has so far declined to support an independent inquiry.