Presidential officials said the investigators presented their findings to President Hamid Karzai, Khaama Press reported Monday.
Karzai appointed the delegation following the U.N. report, which expressed concerns about people held in the Afghan prison system.
The U.N. report said more than 50 percent of the prisoners held in Afghanistan's war were tortured or ill-treated while in custody between October 2011 and October 2012. The report documented 14 different methods of abuse and torture, including electric shocks, twisting of genitals, beatings with cables and rifle butts, and suspension from the wrists or feet.
The report said 326 of 635 prisoners interviewed said they were abused.
Torture rose in Afghan prisons during the past year and there are "credible reports" the country's intelligence service created a network of secret prisons and sometimes hid detainees from international observers, the report said.