Nineteen students accused of cheating on online courses have been suspended from an Atlanta high school.

An Atlanta Public Schools spokeswoman called the case “an isolated incident.”

The alleged cheating comes after staff at the same school warned the school board that students in online classes were awarded grades they did not earn. And it comes a year after students at another Atlanta high school used a teacher's account to change online course grades.

In Atlanta, as in many districts nationally, more students are taking classes online as part of regular instruction and to make up credit for failed classes. Atlanta's expanding use of online classes includes the use of "blended learning" at Crim, which entails online coursework supervised by in-person teachers.

Crim focuses on teaching students who haven’t succeeded at other high schools. District officials have said blended learning has particular potential to help those students because it allows them to learn at their own pace.

Most classes at Crim are taught online, with teachers supervising rooms of students.

This year at Crim, students used a staff member’s log-on information to alter their own information within the online course system, district spokeswoman Kimberly Willis Green said.

“Although the students were able to access assignments and tests, the program’s internal controls alerted the teacher to review all student submissions. Therefore, the students’ changes were not recorded in our grading system,” Green said in a written statement.

It's a different kind of cheating than the allegations about online courses at Crim last year, which involved accusations that students had Googled their way to diplomas.

But at Atlanta's Therrell High School last spring, students also used a teacher's credentials to change grades in their online coursework, according to an internal district report.

The Therrell teacher, who has since resigned, suggested her log-on information had been stolen. Teachers’ laptops had been stolen by students and teachers’ user IDs and passwords were easy for students to figure out, she told district investigators. But the investigators found she had logged on to the online course system herself and allowed students to enter their own grades.

The district has confidence in the online courses from a company called Edgenuity that are offered at Crim, Green said.

“Edgenuity provides rigorous online educational content that is interactive for students and meets the Georgia Standards of Excellence,” she said in a written statement.

The district already has security procedures that require employees to change their passwords periodically and use strong passwords, she said. The district is also developing a technology-security awareness campaign.

The Crim teacher whose online credentials were compromised this year “was counseled by school administrators on how to safeguard program passwords in the classroom,” Green said, and her password has been changed.