The National Directorate of Security in Afghanistan said it has dropped its investigation into 17 civilian deaths allegedly caused by the United States.
The probe was launched when the men died after being detained during U.S. raids in the central Maidan Wardak province.
The investigation was halted after Afghan authorities were unable to speak to the U.S. forces at the center of the probe, Khaama Press reported Tuesday.
The NDS was attempting to speak to three Green Berets and the four Afghan translators who were working with them.
"Despite many requests by NDS they have not cooperated. Without their cooperation this process cannot be completed," the report said.
The incident took place between October 2012 and February 2012.An Afghan translator, Zakeria Kandahari, was arrested as a suspect in the killings earlier this year.
He said that he was following instructions and claimed that three U.S. troops tortured and killed the civilians.