By Alicia Caldwell
Denver Post Staff Writer

FBI Director Robert Mueller told a local audience Thursday that the nation's response to Sept. 11, 2001, will be judged by not only how aggressively terrorist threats were pursued but also how vigilantly civil liberties were protected.

Mueller spoke to 140 people at The Denver Forum, an issues-oriented club that meets at the Oxford Hotel in Lower Downtown.

In a discussion with reporters after the forum, Mueller said it is imperative to prosecute crimes uncovered during intelligence investigations. It's a practice that became legal with the Patriot Act and the dismantling of the so-called "wall" between spy and criminal probes.

"It would be counterproductive and foolhardy for us, as a country, not to utilize that information and pursue that," he said.

However, he said, using spy operations to fish for crimes is not the same.

"You should not be able to use an intelligence wire to develop a criminal case," he said.

In response to a question about whether it was appropriate for the FBI's local Joint Terrorism Task Force to monitor the protest activities of local activists, Mueller said the agency has an obligation to follow credible leads.

"I can tell you that we don't target groups as such," he said.

The task force and the Denver Police Department have been criticized by the local American Civil Liberties Union and accused of keeping "spy files" on activists engaged in legal activities.