Mehboob Hussain was riding the train home on Tuesday when the tracks under the front car exploded. In the depths of central Pakistan's Bolan Pass, a pocket of wilderness so remote that there is no internet or mobile network coverage, the nine-coach Jaffar Express ground to a halt. Then the bullets started flying.

The BLA is one of the largest militant outfits demanding independence for Balochistan. It is designated as a terrorist group by Pakistan as well as the US.