The families of two journalists beheaded by Islamic State jihadists were both warned by US government officials they could face prosecution if they raised a ransom for their release. The recent executions of James Foley and Steven Sotloff by Islamic State (IS) extremists triggered worldwide revulsion and Washington has since declared it is at war with the radicals. The United States has a policy of never paying ransoms, contending that doing so would endanger Americans all over the world. Late Friday, a spokesman for Sotloff's family said the murdered journalist's parents were told by a White House counterterrorism official last...