WICHITA, Kansas -- Moments after a jury convicted a Kansas lawyer for using the Internet to try to entice a child into sex, a federal judge set him free.

Jan Helder’s attorney successfully argued that his client didn’t break the law because the person he was chatting with online was actually a Platte County, Missouri sheriff’s deputy.

The question now is how this ruling will affect similar sting operations in Kansas.

Helder faced federal charges for trying to entice a 14-year-old girl into meeting him for sex. Prosecutors say he propositioned the minor in a chat room last April but that girl turned out to be an undercover deputy.

It turns out that the sting meant to trap sexual predators is exactly what freed Helder after a jury convicted him.

"This Kansas City case is actually a very important case for it recognizes the federal Congress intended this law to prosecute persons who sexually entice actual children," said Dan Monnat, Wichita defense attorney.

In a defense motion, Helder’s attorney argued the proof in this case does not establish that the person Helder is accused of propositioning was in fact a minor under the age of 18. The issue is best characterized as a legal impossibility.

"In other words, the judge said no crime was committed here because no real child was enticed," said Monnat.

But Monnat says that defense wouldn’t stand in a Kansas state court.

"Because, in Kansas, we have a specific law affectively doing away with legal impossibility as a defense," said Monnat.

But Attorney General Phil Kline is concerned because he pushes to have these cases prosecuted in federal court. Local law enforcement and the local branch of the FBI say they will continue their undercover operations.