DENVER, Colo. -- The city of Denver is spending tens of thousands of tax dollars on trials for DNC protestors charged with blocking a street.

About half of those arrested on Aug. 25, 2008 simply paid the hundred dollar fine and moved on, but CALL7 Investigator John Ferrugia learned fifty people refused to pay and asked for their day in court, costing the city thousands of dollars and hundreds of hours in legal time.

A majority of those fifty people have been acquitted or had the charges dropped.

"We were told we were going to be released," said Stephanie Evans.

Evans told 7NEWS she was arrested while walking home from work as she stopped to watch the protest.

Evans was caught up in a mass arrest.

The protestors were told they could plead guilty, pay a hundred dollar fine and go home or they could go to court.

"There is no way I would plead guilty for something I didn't do, " said Evans.

"These people are all being charged with obstructing a street," said Brian Vicente, Executive Director of the People's Law Project.

He claims the city, in a legal sense, is using a sledgehammer to swat a fly.

Vicente said, "They are sending a message. If you attend a free speech event, the police are going to come after you and the city is going to prosecute you to the fullest extent of the law."

Denver City Attorney David Fine disagreed and said, "We treated these cases the same as any other case."

He said his office spent no additional money and his lawyers do not work by the hour.

But the Denver Police Department, which Fine does not oversee, spent nearly $20,000 and more than 400 man hours preparing for and testifying at the trials.

City records show that 42 of the 93 protestors arrested pleaded guilty and paid the fine.

Fifty protestors were slated for trial and, so far, 12 have been convicted of a misdemeanor, 7 others agreed to a deferred judgment before the trial, and one has an outstanding warrant.

Up to now, 26 people have been acquitted or had the charges dropped before trial.

That's a 38 percent conviction rate on cases slated for trial.

Evans trial lasted three days and she said it took the jury 15 minutes to find her not guilty.

"Should taxpayers be satisfied with your judgment to move these cases forward?" Ferrugia asked Fine.

"Our judgment was that when protestors engage in speech that is not lawful or activity that is not lawful in connection with their speech, and the grounds exist to prosecute them, that we do so. I believe the taxpayers expect my office to make that kind of judgment," said Fine.

But, that may be questioned after the testimony of a key witness for the prosecution.

A 16-year veteran police Sgt. who testified in several protestor trials admitted, under oath, that some of his previous testimony was untruthful.

7NEWS obtained audio tapes of the December trial in which defense attorney Marc Milavitz asked the Sgt. about his previous testimony.

Milavitz: On October 21st, when the question was asked, ‘Is it possible that there were bystanders who ended up getting corralled?’ And you said, ‘that’s possible, yes sir.’

Denver Sgt.: Yes, sir.

Milavitz: Is that truthful and accurate testimony?

Denver Sgt.: That is not truthful and accurate.

Milavitz: So when you testified to that before, you were not being truthful and accurate?

Denver Sgt.: No, sir. And this is why I'm trying to answer the questions to the jury with full disclosure.

Vicente told 7NEWS, "We are concerned about the people that were found guilty based, in part, on his word."

And that could mean appeals and more cost for the city.