A Somali man who acted as a ransom negotiator for pirates who seized an American yacht last year and killed four American hostages was sentenced on Monday by a U.S. federal judge to serve 12 life sentences.Mohammad Shibin was convicted in April on 15 charges including piracy, hostage taking, kidnapping and conspiracy. He was paid $30,000 to $50,000 in cash for his negotiating services, according to a federal indictment.In a courtroom in Norfolk, Virginia, U.S. District Judge Robert Doumar sentenced Shibin to serve 10 concurrent life sentences, two consecutive life sentences and two 20-year sentences and ordered him to pay $5.4 million in restitution."Mohammad Shibin was a key participant in two of the most heinous acts of piracy in modern memory,” U.S. Attorney Neil MacBride said in a statement.Pirates commandeered an American yacht carrying Jean and Scott Adam of California and Phyllis Macay and Bob Riggle from Seattle in February 2011 off the coast of Somalia. All four hostages were killed despite attempts by the U.S. military to negotiate their release.Prosecutors said Shibin was among an elite group whose skills were needed to negotiate ransoms.According to evidence presented at trial, Shibin researched the background of the hostages over the Internet to determine how much ransom to demand and to find family members to contact for the payments, prosecutors said.Shibin also served as a ransom negotiator for pirates who seized the M/V Marida Marguerite in 2010. The German-owned vessel had a crew of 22 men who were held hostage for seven months starting in May 2010 and reported being tortured.In 2011 Somali piracy cost the world economy $7 billion and earned the pirates some $160 million in ransoms, according to a recent report by the International Maritime Bureau."(Shibin’s) multiple life sentences should put all pirates on notice that the Justice Department will hold you accountable in a U.S. courtroom for crimes on the high seas,” MacBride said.