Russia has released former US Marine Robert Gilman on humanitarian grounds after his health sharply deteriorated in prison, Reuters reports. A Russian court initially sentenced Gilman to four and a half years in prison. Gilman's Health Deteriorated Dramatically in PrisonGilman's condition deteriorated dramatically in recent months. Gilman Flies to United States for TreatmentGilman is currently aboard a US State Department aircraft bound for Washington. His release brings to an end more than four years of imprisonment in Russia, during which his legal situation became increasingly complicated and his health deteriorated severely.