Last March, a Fulton County grand jury indicted 35 former Atlanta Public Schools employees in the test-cheating scandal. So far, 18 defendants have pleaded guilty, leaving 16 still under indictment. (Another APS defendant is now deceased.) Those who have pleaded guilty:

Armstead Salters, principal of Gideons Elementary School

Lucious Brown, principal of Kennedy Middle School

Clarietta Davis, principal of Venetian Hills Elementary School

Gregory Reid, assistant principal of Parks Middle School

Starlette Mitchell, teacher at Parks Middle School

Kimberly Oden, teacher at Parks Middle School

Derrick Broadwater, teacher at Dobbs Elementary School

Shayla Smith, teacher at Dobbs Elementary School

Gloria Ivey, teacher at Dunbar Elementary School

Lisa Terry, teacher at Humphries Elementary School

Ingrid Abella-Sly, teacher at Humphries Elementary School

Wendy Ahmed, teacher at Humphries Elementary School

Sheila Evans, teacher at Benteen Elementary School

Francis Mack, testing coordinator at D.H. Stanton Elementary School

Sheridan Rogers, testing coordinator at Gideons Elementary School

Lera Middlebrooks, testing coordinator at Dunbar Elementary School

Tamaka Goodson, school improvement specialist at Kennedy Middle School

Carol Dennis, secretary at Kennedy Middle School

A third principal pleaded guilty Friday in the Atlanta Public Schools test-cheating scandal, giving prosecutors another key witness against school administrators in a forthcoming racketeering trial.

Lucious Brown, who once headed Kennedy Middle School, pleaded guilty to a single felony count and was sentenced to two years on probation. He admitted erasing his students’ answers and changing them from wrong to right on standardized tests given in 2008 and 2009.

Brown, reading a letter of apology, said he must be held accountable and take full responsibility for his “self-centered acts.”

“As a result of my actions, time has vanished, lives have been destroyed, friendships lost, veracity misplaced, academic achievement scarred, the eruption of parental turmoil, the loss of millions of dollars and, most of all, our children are aggressively looking for solutions,” he said.

Brown, who agreed to co-operate in the ongoing prosecution, is expected to testify against defendant Sharon Davis-Williams, the regional School Reform Team director whose office was in Kennedy Middle School.

Kennedy, located in a crime-ridden area known as the Bluff, had terrible disciplinary problems when Brown took over in late 2007. There were frequent fights. Many students arrived late and hungry. Some students cursed at teachers and walked out of school during instruction.

Kennedy was designated a needs-improvement school by the state in 2007, with 40 percent of its student population performing below grade level. Yet Davis-Williams, who was well aware of the problems and the testing data, set unrealistic test goals for Kennedy, Deputy District Attorney Fani Willis said during Friday’s plea hearing.

Kennedy met its test targets in both 2008 and 2009 because of the cheating. “There’s no way (Davis-Williams) didn’t know what was going on,” Willis said.

Brown believed “it would have been obvious to anyone” that the targets set by former Superintendent Beverly Hall, the lead defendant in the case, were “completely unrealistic,” Willis said. Brown also believes Hall knew Kennedy could not meet its APS targets in the time frame allotted without cheating, the prosecutor said.

Brown became the 18th APS defendant to plead guilty. Sixteen defendants remain charged in a racketeering conspiracy and four or five of them are engaged in plea negotiations, Willis said. At Willis’ request, Fulton County Superior Court Judge Jerry Baxter extended his deadline to accept negotiated pleas, giving prosecutors and defendants until Jan. 31 to reach resolutions.

Brown pleaded guilty to interfering with government property — his school’s standardized tests. He was ordered to perform 1,000 hours of community service and return $1,000 he received in bonus pay for his school’s improved test scores. He was sentenced under the First Offender Act, meaning his conviction will be erased if he successfully completes his probation.

Recent guilty pleas by two of Brown’s co-workers appeared to give him little choice but to reach his own deal.

Former secretary Carol Dennis and ex-school improvement specialist Tameka Goodson admitted they helped Brown change students’ answers on standardized tests. They also agreed to testify about the cheating in the trial set for this spring.

Both Dennis and Goodson told prosecutors that Davis-Williams put extreme pressure on Brown. After emerging from one particularly intense meeting with his regional director, Brown looked as if he had been crying, they said.

Prior to the start of the 2008 Criterion-Referenced Competency Tests, Brown asked Dennis and Goodson to help him change answers of “Level I” students — those who were expected to fail the test, Willis said. They agreed and helped Kennedy meet its targets that year and again in 2009.

They also entered into a pact, vowing to “take this secret to their graves,” Willis said. But that was broken with the recent guilty pleas.

Last year, Brown’s lawyer, Brian Steel, attacked the 90-page racketeering indictment, saying that APS defendants gave coerced statements when interviewed by investigators because they had been told they risked losing their jobs if they failed to cooperate.

At the conclusion of lengthy court hearings, Baxter indicated that he agreed the statements had been coerced, raising the possibility that the indictment could be in peril. But the judge reversed course the following week. In his ruling, he handed prosecutors a much-needed victory, finding “there were no expressed threats” that APS officials would lose their jobs.