Top officials at the Bureau of Prisons acknowledged Wednesday that three men imprisoned for bombing the World Trade Center in 1993 wrote about 90 letters to contacts on the outside, not only to a Spanish terror cell, but also to other Islamic extremists. NBC News has learned that some of these letters, written in 2003 and early 2004, went to militants in Morocco, a hotbed of terror recruiting.
"Lord knows what these letters said," says Sen. Charles Schumer, D-N.Y. "I mean, maybe they were just propaganda, maybe they were instructions."
In an interview with NBC's Pete Williams, Attorney General Alberto Gonzales says he's working to fix the problem.
"I don't believe this. That kind of thing shouldn't be happening," says Gonzales. "I was surprised. Didn't seem to make any sense to me and I'm sure the average American would have to wonder, 'How could this happen?'"
Corrections officers at the Supermax prison in Colorado tell NBC News they complained to top prison officials a year and a half ago that letters from the bombers and other terrorists were not being carefully monitored. They say they were ignored.
Justice Department officials say they've imposed new restrictions on letter-writing by the three bombers, because they broke a rule by writing letters to inmates in Spanish prisons.
Joe Mansour, who works at a federal prison in Virginia and has translated in some high-profile terrorism cases, warned two years ago that many "Arabic letters and phone calls are unmonitored due to a lack of Arabic-speaking staff."
"In my opinion, nothing should come out of these prisons without being monitored. Nothing," says Mansour.
However, prison officials argue there have always been plenty of translators. Arabic experts say prison officials underestimated the potential recruiting power of letters from convicted terrorists.
"It's a power that the average person or the average imam in a mosque doesn't have," says Hedieth Mirahmadi, an expert on radical Islam at the American Enterprise Institute.
Senior administration officials say they're now considering tighter restrictions on outside contact by all convicted terrorists.