Query: How many of the men died in prison?
Context: Three of the men were sentenced to death (which was later reduced to life in prison), and the fourth defendant was sentenced to life in prison. Two of the four men died in prison after serving almost 30 years, and two others were released after serving 32 and 36 years. In July 2007, U.S. District Judge Nancy Gertner in Boston found the bureau helped convict the four men using false witness account by mobster Joseph Barboza.