US prisoners often die from HIV/AIDS infection or inadequate medical service. A report released by the US Department of Justice in September 2007 said there were 22,480 state and federal inmates who were HIV infected or had confirmed AIDS at yearend 2005, 5,620 inmates had confirmed AIDS. During 2005 an estimated 176 state and 27 federal inmates died from AIDS-related causes (HIV in prisons 2005, US Department of Justice, www.ojp.usdoj.gov/bjs). According to a report by the Los Angeles Times on September 20, 2007, 426 death cases took place in California prisons in 2006 due to belated treatment. Among them, 18 deaths were found to be "preventable" and an additional 48 were found to be "possibly preventable". On April 14, 2007, 41-year-old diabetic prisoner Rodolfo Ramos died after being left alone and covered in his own feces for a week. Prison officials failed to get medical treatment for him despite knowing of his condition (The Associated Press, April 27, 2007).

The justice of US judicial system was increasingly put in question. Survey finds that since the first DNA exoneration in 1989, there have been 209 post-conviction DNA exonerations in the United States. The average length of time served by exonerees is 12 years. The average age of exonerees at the time of their wrongful convictions was 26, and 15 of the 209 people exonerated through DNA served time on death row (Facts on Post-Conviction DNA Exonerations, Innocence Project, www.innocenceproject.com). The Associated Press reported on January 3, 2008 that Charles Chatman of Texas was proved innocent by DNA evidence after spending 26 years in prison. In 1981, he was sentenced to 99 years in prison after convicted of committing serious sexual assaults. He was the 15th inmate exonerated by DNA evidence in Dalas since 2001 (Texas Man Exonerated by DNA After 26 Years, the Associated Press, January 3, 2008).