Jay Austin and Lauren Geoghegan were run over by a car in Tajikistan, deliberately.
A grainy cellphone clip recorded by a driver shows what happened next: The men's Daewoo sedan passes the cyclists and then makes a sharp U-turn. It doubles back, and aims directly for the bikers, ramming into them and lurching over their fallen forms. In all, four people were killed: Mr. Austin, Ms. Geoghegan and cyclists from Switzerland and the Netherlands.
Two days later, the Islamic State released a video showing five men it identified as the attackers, sitting before the ISIS flag. They face the camera and make a vow: to kill "disbelievers."
"With...vulnerability," he wrote, "comes immense generosity: good folks who will recognize your helplessness and recognize that you need assistance in one form or another and offer it in spades."