Thomas Edward Silverstein was an American criminal who spent the last 42 years of his life in prison after being convicted of four separate murders while imprisoned for armed robbery, one of which was overturned. Silverstein spent the last 36 years of his life in solitary confinement for killing corrections officer Merle Clutts at the Marion Penitentiary in Illinois. Prison authorities described him as a brutal killer and a former leader of the Aryan Brotherhood prison gang. Silverstein maintained that the dehumanizing conditions inside the prison system contributed to the three murders he committed. He was the longest-held prisoner in solitary confinement within the Bureau of Prisons at the time of his death. Correctional officers refused to talk to Silverstein out of respect for Clutts.

The United States Penitentiary, Marion is a large medium-security United States federal prison for male and female inmates in Southern Precinct, unincorporated Williamson County, Illinois. It is operated by the Federal Bureau of Prisons, a division of the United States Department of Justice. The facility also has an adjacent satellite prison camp that houses minimum security male offenders.