US man marks 4 years in Cuban prison, writes Obama An American man who is marking four years in prison in Cuba has written a letter to President Barack Obama asking the president to get personally involved in securing his release. Alan Gross was arrested four years ago Tuesday while working covertly in the Communist-run country to set up Internet access for the island's small Jewish community, access that bypassed local restrictions. At the time, he was working as a subcontractor for the U.S. government's U.S. Agency for International Development, which works to promote democracy on the island. Cuba considers USAID's programs illegal attempts by the U.S. to undermine its government, and Gross was ultimately tried and sentenced to 15 years in prison. His case has become a sticking point in improving ties between the two countries, which have not had formal diplomatic relations since 1961. "It is clear to me, Mr. President, that only with your personal involvement can my release be secured," Gross wrote in a letter released Tuesday. I know that your administration and prior administrations have taken extraordinary steps to obtain the release of other U.S. citizens imprisoned abroad - even citizens who were not arrested for their work on behalf of their country. I ask that you also take action to secure my release, for my sake and for the sake of my family. Gross, 64, says he has "lost almost everything" over the past four years and that his family "has suffered tremendously." With the utmost respect, Mr. President, I fear that my government - the very government I was serving when I began this nightmare - has abandoned me. Officials in your administration have expressed sympathy and called for my unconditional release, and I very much appreciate that. But it has not brought me home," he wrote. The State Department on Monday called on the Cuban government to release Gross. In late November, 66 senators led by Sen. Patrick Leahy, D-Vt., sent Obama a letter asking him to "act expeditiously to take whatever steps are in the national interest" to obtain Gross' release. White House press secretary Jay Carney said in February that Obama has "followed Mr. Gross' case with concern and urges his release." Gross' wife, Judy Gross, who now lives in Washington, plans to hold a vigil Tuesday in front of the White House to urge the president to help obtain her husband's release. Cuba has previously expressed a willingness to release Gross if the United States makes a similar gesture involving the so-called Cuban Five, intelligence agents who were sentenced to long jail terms in the United States in 2001. One of the men was released from prison in 2011 and was allowed to return to Cuba this year. A second is scheduled for release in February. The United States has in the past ruled out a trade. Over the past year, U.S and Cuban officials have made some progress on repairing their relationship. U.S. and Cuban representatives met twice this year for renewed talks on re-establishing direct mail service, 50 years after it was stopped amid Cold War tensions. The two countries also resumed talks this year about migration issues. Both sets of talks had been on hold since Gross' arrest.