KARACHI, Pakistan (Reuters) - Pakistan's Supreme Court on Thursday ordered the release of an Islamist convicted of beheading U.S. journalist Daniel Pearl, a decision that has left his family in "complete shock", lawyers said. Ahmed Omar Saeed Sheikh, who was the main suspect in the 2002 kidnapping and murder of Wall Street Journal reporter Pearl, was acquitted by a panel of three judges. "By a majority of two to one, they have acquitted all the accused persons and ordered their release," a provincial advocate general, Salman Talibuddin, told Reuters. Pearl, 38, was investigating Islamist militants in Karachi after the Sept. 11, 2001, attacks on the United States when he was kidnapped. His case grabbed headlines globally after a video of his beheading emerged weeks after he was abducted. Sheikh and his co-accused are to be released immediately if they aren't required in any other case, the head of the court panel, Justice Mushir Alam, said in a short court or