KABUL, Afghanistan - Three Americans arrested in Afghanistan were on a self-appointed counterterrorism mission that included holding eight inmates in a private jail, a senior official said Thursday. U.S. officials identified one of the men detained Monday in a raid in Kabul as Jonathan K. Idema, a purported former Green Beret who claims to have links with Afghan militia forces. The American military has warned that Idema had been posing as a U.S. military or government employee. Interior Minister Ali Ahmad Jalali said the three men had, along with four Afghans also arrested Monday, "formed a group and pretended they...