Prisoners who died in Massachusetts detention

John C. Salvi III (March 2, 1972 – November 29, 1996) was an anti-abortion extremist who carried out fatal shootings at two abortion facilities in Brookline, Massachusetts on December 30, 1994. The shootings killed two and wounded five. An insanity defense at his trial was not successful and he was convicted of two counts of murder and sentenced to life in prison without the possibility of parole. He died in 1996 in what was officially ruled a suicide in his jail cell.

Antone Charles "Tony" Costa (August 2, 1944 – May 12, 1974), sometimes referred to as the Cape Cod Vampire or the Cape Cod Cannibal, was an American serial killer who was active in and around the town of Truro, Massachusetts, during 1968–1969. The dismembered remains of four women were found in or near a forest clearing where Costa grew marijuana. His crimes gained international media attention when the district attorney falsely alluded to cannibalism.