John Cichy walked out of the DuPage County courthouse a free man on Tuesday, which was when his bench trial was scheduled to start.
"My client was insistent all along that what they were charging him with was not what he participated in," said Jay Fuller, Cichy's attorney.
In 2013, Cichy was accused of conspiring with two other officers to confiscate drugs from dealers and sell them for profit through other dealers.
The case led to guilty pleas from the other officers -- Matthew Hudak and Terrence O'Brien. They were set to testify against Cichy.
The state's attorney's office cited ethical obligations when they dropped the charges.
In a written statement, DuPage County State's Attorney Robert Berlin said: "If at any point during this time the evolution of a case is such that the facts and circumstances will no longer result in a successful prosecution, the law demands that the prosecution cease."
Fuller attributes the collapse of the case to the criminal informant the prosecution built their case around.
"When you base the prosecution on that type of witness things like this happen, where five years down the road the state is forced to dismiss a case," Fuller said.
Attorneys for Hudak and O'Brien wonder what this means for their clients, questioning the recent developments.
"If it's the same evidence and that evidence has not been deemed sound by the prosecution then why should they continue to be held to that standard," said Thomas Glasgow, Hudak's attorney.