U.S. opens criminal probe of journalist Foley's death - Holder

WASHINGTON (Reuters) - The U.S. Justice Department is conducting a criminal investigation of the death of American journalist James Foley, Attorney General Eric Holder said on Thursday.

Foley was beheaded by the Islamist militant group Islamic State, an act shown in a video released on Tuesday in which the group called for the United States to end its air strikes in Iraq. President Barack Obama responded that the United States would be relentless in fighting the organisation despite the killing.