The number of terrorism cases brought by the US Justice Department, which surged in the aftermath of the Sept. 11, 2001, terrorist attacks, has dropped sharply since 2002, and prosecutors are turning down hundreds of cases because of weak evidence and other legal problems, according to a study released on Sunday.
The study, conducted by a private research group at Syracuse University, found that federal prosecutors have declined to prosecute two of every three international terrorism cases brought to them by the FBI and other agencies since 2001.
The rejection rate was even higher for the first eight months of the current fiscal year, with 91 percent of the referred cases turned down for prosecution, the research group said.
Among the most frequent explanations cited by prosecutors, the study found, were a lack of evidence of criminal intent by the suspect and "weak or insufficient" evidence.
The numbers brought differing interpretations from legal analysts, prosecutors, and government officials, many of whom were surprised by the findings, and are likely to add to the debate over the administration's tactics in prosecuting the fight against terrorism. The Justice Department immediately took issue with the study's methodology and its conclusions.
The study "ignores the reality of how the war on terrorism is prosecuted in federal courts across the country and the value of early disruption of potential terrorist acts by proactive prosecution," said Bryan Sierra, a Justice Department spokesman.
"The report presents misleading analysis of Department of Justice statistics to suggest the threat of terrorism may be inaccurate or exaggerated," Sierra added.
"The Department of Justice disagrees with this suggestion completely," he said.
Department officials declined to discuss details of what they considered the flawed methodology.
Since the Sept. 11, 2001, attacks, the Bush administration has pursued a strategy of investigating and prosecuting terrorism suspects within the US to "pre-empt" attacks, rather than waiting for them to unfold.
The strategy, which administration officials say helps explain the absence of any further attacks on American soil, has been seen in cases like the arrests of seven men in Miami in June in a plot that the FBI said was "more aspirational than operational."
The approach has led critics of the Bush administration to say that prosecutors are routinely bringing terrorism charges in cases that do not warrant them. But the data from the Syracuse group suggests that for every prosecution like the one that occurred in Miami, there are many other investigations around the country that never become public because prosecutors conclude there is not enough evidence to take them to court.
The FBI and other federal agencies bring what are known as referrals in cases in which the investigating agency recommends that federal charges be considered, often after investigations lasting months or years.
RSS