From the battlefield near Baiji, an Islamic State jihadist fired a heat-seeking missile and blew an Iraqi Army Mi-35M attack helicopter out of the sky this month, killing its two crew members.

Days later, the Islamic State released a chilling series of images from a video purporting to capture the attack in northern Iraq: a jihadist hiding behind a wall with a Chinese-made missile launcher balanced on his shoulder; the missile blasting from the tube, its contrail swooping upward as it tracked its target; the fiery impact and the wreckage on a rural road.

The helicopter was one of several Iraqi military helicopters that the militants claim to have shot down this year, and the strongest evidence yet that Islamic State fighters in Iraq are using advanced surface-to-air missile systems that pose a serious threat to aircraft flown by Iraq and the American-led coalition. […]