Students at an Atlanta high school had failing grades mysteriously changed to passing, much to their teacher’s surprise, back in 2011, and Atlanta Public Schools finished investigating it last September.

An entire class at the same school — Mays High School — got passing marks after their teachers had not graded them, according to an internal district report obtained by The Atlanta Journal-Constitution this week under state public records laws.

During the intervening 3 years — while the district was consumed with a criminal investigation into cheating on state tests mostly in elementary schools — other investigations had “priority status,” investigators wrote. Meanwhile, district records show Atlanta high school staff were also under pressure to improve their schools’ stats.

After the Atlanta Journal-Constitution and Channel 2 Action News reported this spring on questions about academic integrity at several Atlanta high schools, Superintendent Meria Carstarphen ordered a district-wide review of grading practices.

“This review did not identify additional cases of serious inappropriate actions, although we did find inconsistencies in practice, lack of clarity in process, and a lack of the necessary safeguards to effectively prevent inappropriate activity,” district accountability chief Bill Caritj wrote in the district review that included Mays High School.

He recommended nearly a dozen changes to the district’s grading systems. Carstarphen has said that any future investigations into complaints of improper grading practices should be completed in under 30 days.

“We have to do the right thing at the right time for the right reason, every single time,” she told the AJC last month.

Teacher Joshua McAboy told district investigators in 2012 that Mays administrators would “target” teachers who failed more than 10 percent of their students and coerce them into passing more students. Investigators didn’t look into those allegations because McAboy declined to give them the names of “targeted” teachers.

McAboy told investigators he had been surprised to learn that one of his students — a football player — had a failing grade of 55 he earned in 2011 mysteriously changed to a passing grade of 70. The student “was just as surprised,” McAboy told investigators. Two other students also had their grades mysteriously raised.

Records authorizing those changes were missing, investigators found, and the school’s registrar was unable to explain the disappearance.

And after a series of substitute teachers replaced McAboy for much of the 2012-13 school year, his students didn’t receive any real evaluation of their work, according to the district report. After learning of the missing grades, Mays academy leader Jane Martin had the registrar give everyone B’s for mid-term grades. Martin did not return a phone message left Wednesday at a number listed for her.

A secretary at another Atlanta high school, Carver School of Technology, lost her job this spring after complaining about a similar practice.

Martin and the Mays registrar told investigators the practice had been common at Mays, authorized by the school’s longtime principal, Tyronne Smith.

Smith was accused in at least five earlier cases that raised questions about academic integrity at Mays. District investigators said they couldn’t prove any of those allegations. He was removed from Mays in 2014 by former superintendent Erroll Davis and reassigned to the central office. He retired last school year, APS spokesman James Malone said.

Martin remained as an academy leader at Mays last year. This year, she’s working as an elementary school teacher, Malone said.

District investigators said they found no evidence showing Smith or Martin improperly changed student grades. But they faulted both for issuing arbitrary grades — a violation of Georgia’s professional standards for educators.

Officials with the state agency that oversees educator licensing said they have no record that APS informed them of the findings against Smith or Martin. Malone, the APS spokesman, said if Martin’s case has not already been referred to the state, it will be soon.