At first, math coach Arn St. Cyr was happy to see double-digit performance improvements at Harper-Archer Middle School on the spring 2009 state math tests after years of working closely with students.

“Everybody assumed that finally what we were doing was paying off,” he said.

Then his attitude changed.

“Once we started looking at the numbers it was obvious that something was wrong,” he said. “You can reasonably expect maybe 10 percent a year. To see a 30-percent jump, that was unheard of. It just didn’t add up to me.”

Like former Harper-Archer Middle School principal Michael Milstead, St. Cyr testified that he was not told to cheat on state tests and that he didn’t change answers on tests.

But he said he had no plausible explanation for the 2009 test results other than that cheating had occurred.

APS trial: Former APS principal: Test-score gains didn’t seem real — 11:46 a.m.

After staff from the Atlanta Public Schools central office and the office of regional executive director Tamara Cotman “monitored” testing at Harper-Archer Middle School, the school saw double-digit improvements on state math tests.

“We were ecstatic,” former principal Michael Milstead testified Monday in the APS test-cheating trial.

But Milstead said the more he thought about it, the more he realized the gains were not legitimate.

“[I] was trying to make it seem like it was real but it was very difficult,” he said. “That type of gain was very hard to achieve, especially in math.”

Milstead said he did not change any answers on the 2009 Criterion-Referenced Competency Test, but he suspected some people did. He said too that Cotman never told him to cheat.

State investigators later found that cheating had occurred at the school. Although none of the 52 people investigators interviewed confessed to cheating, teachers “almost unanimously” said they agreed cheating had occurred.

In 24 classrooms, the probability that the number of wrong to right erasures on test answer sheets had happened without cheating were no better than one in a trillion, according to the 2011 state investigative report.

Milstead is the first in the series of a prosecution witnesses expected to testify in the state’s case against former regional director Tamara Cotman. He previously testified against her in a 2013 trial in which Cotman was acquitted of a charge of influencing a witness. She is now standing trial on a single felony racketeering charge.

Milstead resigned in 2009 before the district could end his employment.

APS trial: Focus turns to Cotman - 7:44 a.m.

The Atlanta Public Schools test-cheating trial resumes today and the prosecution’s focus turns to Tamara Cotman, a regional supervisor who oversaw 21 schools.

Cotman is one of 12 former educators and administrators on trial for allegedly participating in a racketeering conspiracy to inflate scores on state-mandated standardized tests.

Witnesses expected to testify this week include those who took the stand in the first trial involving Cotman, in which she was found not guilty.

That trial, in September 2013, was held because Cotman’s lawyer filed a speedy trial demand after prosecutors re-indicted Cotman on an influencing a witness charge.

Prosecutors alleged she influenced a witness who claimed Cotman instructed principals to tell state investigators to “go to hell.” Witnesses testified that Cotman handed out “go to hell” notes as a stress-relief exercise during a meeting, not to discourage educators from talking to investigators. Jurors said they found the evidence lacking and acquitted her.

After the verdict, Cotman said the evidence and the jury vindicated her.

“I’ve always said that I serve a God of truth and that the truth will set you free. And today I feel free, ” Cotman said at that time. “I was just grateful that the jurors listened to all the evidence and were able to filter the truth from things that weren’t true.”

Cotman was not off the hook yet. During the ongoing trial, she faces a single felony racketeering charge.