(Reuters) - At least three members of a high school football team in Steubenville, Ohio, received word they would not be prosecuted just days before testifying against teammates accused of raping a 16-year-old girl, according to documents obtained by Reuters.

In letters from Ohio Attorney General Mike DeWine's office addressed to each student's lawyer, the state committed to not prosecuting Evan Westlake, Anthony Craig and Mark Cole, three witnesses for the prosecution.

But DeWine said on Thursday his office had made no deal with any of the witnesses involved in the case.

"We have offered nothing, made no promises to any witness in this case. ... No deals have been cut with anybody," DeWine told WTOV television in comments confirmed by his spokesman.

The case has unsettled Steubenville, a city of 19,000 near the Pennsylvania border where football has a powerful influence.

Community leaders have criticized authorities, voicing suspicion they have avoided charging more players who could have been involved in order to protect the school's beloved football program.

Days after the letters were sent, all three players testified at a pre-trial hearing against teammates Ma'lik Richmond and Trenton Mays, both 16, who were charged with raping a classmate at a party attended by many teammates last August. Richmond and Mays were set to be tried as juveniles in February.

Although evidence in the criminal case showed each player "may not have conducted himself in a responsible or appropriate manner, his behavior did not rise to the level of any criminal conduct," all three letters say. "Therefore, we will not prosecute your client for his actions on August 11-12, 2012."

Walter Madison, an attorney who represents one of the students charged with rape, verified the letters' authenticity, but declined to comment further.

The letters can protect the players from criminal charges, said John Burkoff, a criminal law professor at the University of Pittsburgh.

"If the government says that it won't prosecute you and then changes its mind, you can argue that it can't go back on that," he said. "It's constitutional estoppel (an impediment)."

The letter to Westlake, dated September 28, was signed by Ohio Associate Attorney General Marianne Hemmeter. The other two letters were signed by Ohio Associate Assistant Attorney General Jennifer Brumby and dated October 9, three days before the trio testified against their teammates. Brumby and Hemmeter conducted the questioning at that hearing.

Attorney General spokesman Dan Tierney said the state decided the students would go uncharged only for the crime of illegal use of a minor in nudity-oriented material.

"We would stand by the attorney general's previous comments," he told Reuters on Thursday.

The case shot to national prominence last week when the online activist group Anonymous made public a picture of the purported rape victim being carried by her wrists and ankles by two young men. Anonymous also released a video that showed several other young men joking about an assault.