Federal prison officials are failing to monitor mail to and from convicted terrorists and other high-risk prisoners, a Justice Department review concluded Tuesday. The review also found that gaps in mail monitoring have increased from a year ago, with prison investigators now reading less inmate mail at seven of 10 prisons surveyed by the Justice Department s inspector general. The threat remains that terrorist and other high-risk inmates can use mail and verbal communications to conduct terrorist or criminal activities while incarcerated, concluded the inspector general s report of U.S. Bureau of Prisons facilities. The mail investigation was spurred, in part, by the discover that three convicted terrorists at a federal maximum-security prison in Florence, Colorado, were found to have written an estimated 90 letters to Islamic extremists including some with links to the March 11, 2004 attacks in Madrid. Some of the letters, written between 2002 and 2004, later surfaced in the hands of a terror suspect who used them to recruit suicide operatives. Following that discovery, the Bureau of Prisons took steps to limit high-risk inmates mail and telephone calls. It also hired more Arabic translators and sought to better analyze mail for clues to suspicious or criminal activity. But limited funding and a growing inmate population has hindered those efforts, the report concluded. Federal prisons and detention facilities housed more 191,000 inmates as of July, a 70 percent increase over the last decade. An estimated 10 percent of those inmates, or 19,720, are considered high risk including domestic and international terrorists and leaders and members and gangs. The number of high-risk inmates similarly increased, by 60 percent, during that period. By contrast, federal prisons staff grew by only 14 percent over the decade. The Bureau of Prisons expects its staff to read 100 percent of high-risk inmate mail, including translating documents written in foreign languages, but no tracking system is in place to ensure that target is met.