What happened

An Afghan contractor employee, Ahmad Nayeb — a former Taliban insurgent hired by a US contractor in 2011 — detonated a suicide vest during a pre-dawn Veterans Day fun run at Bagram Airfield on 12 November 2016, killing three American soldiers and two civilian contractors immediately, with a fourth soldier later dying of wounds; 16 American soldiers and one Polish soldier were also wounded. A subsequent US Army investigation, reported by Army Times in December 2017, found Nayeb had spent roughly four months building the vest in his on-base workspace, was able to check out a multimeter needed for bomb-making nine times without restriction, and had a history of unexplained absences that went undisciplined; his past insurgent ties were never flagged to counterintelligence. The report described a 'culture of complacency' among civilian base personnel that enabled the attack.

When cited sources give different casualty, damage or spill figures for this event, they’re reported side by side above rather than merged into one number. See how confidence levels work.