After the four Kennedy Middle School colleagues huddled together and changed students’ answers on state tests, they made a solemn pledge to take their secret to their graves.

That agreement lasted only so long, Lucious Brown, Kennedy’s former principal, testified Monday. On the witness stand in the Atlanta Public Schools test-cheating trial, Brown disclosed how he came up with the idea and how they surreptitiously erased answers in his conference room.

Brown, who pleaded guilty in January, is one of the state’s key witnesses against former regional superintendent Sharon Davis-Williams, one of 12 defendants on trial.

But Brown did not directly tie his former boss to the cheating, saying no one told him to correct wrong answers. And Fulton County Superior Court Judge Jerry Baxter allowed prosecutor Clint Rucker to cross-examine Brown, designating him as a “hostile” witness.

Brown did testify, however, that Davis-Williams “knew my data,” suggesting that she knew Kennedy’s students were struggling and were unlikely to meet targets set by the district.

Brown pleaded guilty to a single felony: interference with government property, his school’s standardized tests. He was sentenced to two years on probation and ordered to perform 1,000 hours of community service and return $1,000 in bonus money. He was also sentenced under the First Offender Act, meaning if he successfully completes his probation he will not have a conviction on his record.

Under the terms of his plea deal, Brown said that Davis-Williams applied pressure for Kennedy to meet state test performance targets set by the district and the Adequate Yearly Progress targets set under the federal No Child Left Behind Act. The targets were unreasonable for a school like Kennedy, where nearly all students were from low-income families and living in a crime-plagued neighborhood, his plea agreement said.

“I just met with Dr. Davis-Williams and we have to make those targets and (Adequate Yearly Progress),” Brown told his Kennedy colleagues before the 2008 state tests, the agreement said. “We have to make it happen.”

But when asked Monday, Brown said the pressure came from the students themselves and their parents who wanted them to succeed, and that he put pressure on himself.

“I did it,” Brown said of the test-cheating. “No one asked me to do it.”

Why did you do it? prosecutor Clint Rucker asked.

“I didn’t want to be associated with failure,” Brown explained. “… It was truly a wrong and an immoral act.”

Starting in 2008, Brown said he and three women — Kennedy’s former secretary, a school improvement specialist and a substitute teacher — changed students’ answers. Brown, a former math teacher, focused on “correcting” answer sheets for math tests, and the others focused on English language arts answers. Before being interviewed by investigators, all swore they would “take this secret to their graves” and deny involvement in changing student answers, according to Brown’s plea deal.

Brown said he not only calculated how many students needed to pass for the school to meet state and district goals, but also which specific students needed to pass.

Until the cheating, Kennedy students showed incremental improvements, but not enough to meet the goals.

After Brown and his colleagues went to work in the conference room, Kennedy’s gradual improvement accelerated dramatically.

Brown’s 2008 personnel evaluation shot up in line with rising test scores. He got a $1,000 bonus that year.

The following year, targets rose again. And the cheating at Kennedy continued, Brown said.