NYTimes.com
by C. J. Chivers April 27, 2015

Early one morning in late February, a European investigator working in Kobani, the northern Syrian city that for months had been a battleground between Kurdish fighters and militants from the Islamic State, stepped outside the building where he was staying and saw something unusual. A Kurd on the street was carrying a long black assault rifle that the investigator thought was an American-made M-16.  More