Eleven former Atlanta public school educators were found guilty by a jury on Wednesday on charges of racketeering in one of the largest U.S. test-cheating scandals, widely followed for years amid a growing debate about high-stakes standardized testing.

During a trial lasting nearly six months, prosecutors accused a dozen former teachers, principals and administrators of erasing incorrect answers or instructing students to change their answers to secure promotions and cash bonuses in 2009.

Eleven of the 12 defendants, found guilty of racketeering, left the courtroom in handcuffs. Some were also convicted on lesser charges, such as making false statements.

They will be jailed until their sentencing later this month and face up to 20 years in prison.

Only one educator was found not guilty on all counts.

The jury reached its verdict on the eighth day of deliberations in a case that ensnared nationally prominent leaders of an urban school district that had seemed to be making remarkable strides.

"Our entire effort in this case was to get our community to look at our educational system," said Fulton County District Attorney Paul Howard. "We've been fighting for the children in our community."

The Atlanta case was the most high-profile of the cheating cases in 40 states and Washington, D.C., that have been tracked in the last five years by the National Center for Fair and Open Testing, known as FairTest, a nonprofit scrutinizing practices.

"It had a huge national impact on the detection and prosecution of cheating," said Bob Schaeffer, its education director.

He said many states and communities responded by adding screening and data analysis to identify signs of cheating.

The convicted Atlanta educators were among 35 teachers, principals and administrators indicted in 2013 after a state investigation found widespread cheating on standardized tests. The defendants opted to stand trial, rather than plead guilty like most others.

Former Atlanta Superintendent Beverly Hall, named National Superintendent of the Year during the period when the cheating occurred, was among those indicted.

Hall's case was put on hold for medical reasons, and she recently died of breast cancer.

The cheating was in response to pressure to meet test targets, state investigators found.

Defense attorneys argued that there was no conspiracy and that prosecutors had pressured educators to testify against their former colleagues.

"I'm devastated," said defense attorney Bob Reuben, representing a former principal. "Errors were made that can be raised on appeal."