A Somali man who acted as a ransom negotiator for pirates who seized a United States yacht last year and killed four US hostages has been sentenced by a US 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 US$30,000 to US$50,000 in cash for his negotiating services, the indictment shows. In a court in Norfolk, in the state of Virginia, on Monday, US 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 US$5.4 million in restitution. "Mohammad Shibin was a key participant in two of the most heinous acts of piracy in modern memory," US Attorney Neil MacBride said. Pirates commandeered a US yacht carrying Jean and Scott Adam and Phyllis Macay and Bob Riggle in February last year off the coast of Somalia. All four hostages were killed despite attempts by the US 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 a German-owned vessel in 2010. It had a 22-man crew who were held hostage for seven months in 2010. "[Shibin's] multiple life sentences should put all pirates on notice that the [US] will hold you accountable in a US courtroom for crimes on the high seas," MacBride said.