Theodore Kaczynski, more widely known as the “Unabomber” for killing three people and injuring many more in a series of mail bombings over 17 years — has been transferred to a federal prison medical facility known for treating inmates with significant health problems, the Washington Post reports. Kaczynski was transferred Dec. 14 from the supermax prison in Florence, Co., where he was serving multiple life-in-prison sentences, to the Butner a federal medical center in North Carolina. David Kaczynski, Ted Kaczynski’s brother, said that the Bureau of Prisons declined to tell him why his brother was being transferred. David Kaczynski, who tipped the FBI to his brother as a possible suspect, said his brother does not respond to his letters. Ted Kaczynski, 79, pleaded guilty in 1998 to arranging mail bombings in a deranged campaign against modern technology. Among the victims of 16 bombs were a Yale computer scientist, an astronaut candidate, a forestry lobbyist, a public relations executive and the president of United Airlines. His plea deal allowed Kaczynski to avoid the death penalty, though his sentence barred the possibility of release. Attorney General Merrick Garland, who worked in the Justice Department when Kaczynski was arrested and helped supervise the prosecution, has said it was one of his most important cases.