JENA, LA. — A black teenager whose prosecution in the beating of a white classmate prompted a massive civil rights protest here walked out of a courthouse yesterday after a judge ordered him freed.

Mychal Bell’s release on $45,000 bail came hours after a prosecutor confirmed he would no longer seek an adult trial for the 17-year-old. Bell, one of the teenagers known as the Jena Six, still faces trial as a juvenile in the December beating in this small central Louisiana town.

“We still have mountains to climb, but at least this is closer to an even playing field,” the Reverend Al Sharpton, who helped organize last week’s protest, said. District Attorney Reed Walters’s decision to abandon adult charges means that Bell, who had faced a maximum of 15 years in prison on his aggravated second-degree battery conviction last month, instead could be held only until he turns 21 if he is found guilty in juvenile court.

The conviction in adult court was thrown out this month by the state 3rd Circuit Court of Appeal, which said Bell should not have been tried as an adult on that particular charge.

Mr. Walters had said he would appeal that decision. Yesterday, he said he still believes there was legal merit to trying Bell as an adult but decided it was in the best interest of the victim, Justin Barker, and his family to let the juvenile court handle the case.

“They are on board with what I decided,” Mr. Walters said at a news conference. Mr. Walters said Bell faces juvenile court charges of aggravated second-degree battery and conspiracy to commit that crime. Bell is among six black Jena High School students arrested in December after a beating that left Mr. Barker unconscious and bloody, though the victim was able to attend a school function later the same day. Four of the defendants were 17 at the time, and legally adults under Louisiana law.

Those four and Bell, who was 16, all were initially charged with attempted murder. Mr. Walters has said he sought to have Bell tried as an adult because he already had a criminal record, and because he believed Bell instigated the attack.

The charges have been dropped to aggravated second-degree battery in four of the cases. One defendant has yet to be arraigned. The sixth defendant’s case is sealed in juvenile court.

Critics accuse Mr. Walters, who is white, of prosecuting blacks more harshly than whites. They note that he filed no charges against three white teenagers suspended from the high school for allegedly hanging nooses in a tree on campus not long before fights between blacks and whites, including the attack on Mr. Barker.

An estimated 20,000 to 25,000 protesters marched in Jena last week in a scene that evoked the early years of the civil-rights movement.

Mr. Walters said the demonstration had no influence on the decision he announced yesterday, and ended his news conference by saying that only God kept the protest peaceful.

“The only way — let me stress that — the only way that I believe that me or this community has been able to endure the trauma that has been thrust upon us is through the prayers of the Christian people who have sent them up in this community,” Mr. Walters said.

“I firmly believe and am confident of the fact that had it not been for the direct intervention of the Lord Jesus Christ last Thursday, a disaster would have happened. You can quote me on that.”