Four people are in custody amid a terror investigation into a beheading and explosion outside a gas factory in southeastern France, according to a French prosecutor. One person was beheaded, and two were hurt in a blast just after after a car drove up to American-owned Air Products' plant in Saint-Quentin Fallavier, authorities said earlier Friday. French officials said the man detained in the attack had worked for the beheaded businessman; he, his wife, his sister and another suspect were in custody, the prosecutor said. A severed head was hanging on a fence by a nearby road, and an Islamist flag was found nearby, a local newspaper reported. French President Francois Hollande said the attack bore the hallmarks of terrorism. The country has been on high alert since deadly attacks in January on satirical magazine Charlie Hebdo and a kosher supermarket.
