Al Qaeda terrorists may have developed undetectable liquid bombs prompting America to evacuate its citizens from Yemen, it emerged today. The explosive would be applied wet to clothing and then detonated when dry, according to senior US officials. Security experts fear it would be completely undetectable using the current range of security devices operated at airports across the world. The terrifying technology is thought to be the work of Al-Qaeda's master bomb-maker Ibrahim al-Asiri who is linked to the Al Qaeda in the Arabian Peninsula (AQAP) group based in the Yemen. Al-Asiri is believed to be the man behind a...