Rape and other forms of sexual abuse have been a recurring issue in the US prison system. Last year, the US Court of Appeals for the First Circuit [official website] ruled [opinion text; JURIST report] that a Massachusetts regulation prohibiting prisoners from receiving sexually explicit mail is constitutional. The Massachusetts prison commissioner defended the regulation on the grounds that it was designed to promote prison safety and security. The DOJ reported [text, PDF] in 2006 that sexual violence in US prisons often goes unreported [JURIST report] because victims fear further abuse or do not trust prison staff. In 2005, the DOJ released its first report [text, PDF; JURIST report] on prison rape in accordance with the Prison Rape Elimination Act of 2003 [DOJ backgrounder], but admitted that most incidents were probably never reported and that their numbers could not be reliably estimated. The NPREC was created pursuant to the Prison Rape Elimination Act, which called for the development of national standards for correctional facilities to eliminate prison rape.