The U.S. Department of Education is investigating the high rate at which black students are disciplined in Seattle Public Schools, a problem that has plagued the district for decades.

Spokesman Jim Bradshaw confirmed to the Associated Press on Tuesday that the department's Office of Civil Rights is looking into whether the district discriminates against black students by disciplining them more frequently and more severely than white students.

According to district data, in the 2011-2012 school year, nearly 13 percent of black high school students received at least one short-term suspension. The equivalent figure for white students was just under 4 percent. In middle schools, the rate was 7 percent of white students and 27 percent of blacks.

The district has long been aware of the disparity, and recently held community meetings that addressed its discipline rates.

The investigation was instigated by the department on its own, rather than by a complaint filed by someone else, Bradshaw said to the Associated Press.

He noted that a similar investigation into Delaware's largest school district, the Christina School District in Wilmington, concluded that black students were disciplined more harshly and more frequently because of their race. Last December, school officials entered an agreement with the Education Department to try to fix the problem, promising to address misbehavior in ways that don't require removal from school, while collaborating with experts on preventing discrimination in discipline and providing training for staff and administrators.

"In virtually all cases, if noncompliance is found, we're able to reach voluntary resolution agreements to help a district or institution come into compliance with our civil rights laws," Bradshaw wrote in an email to the Associated Press. "Enforcement options do exist, but in nearly every case, we're able to work with districts, short of having to resort to that option."

Seattle Public Schools officials told KIRO 7 Eyewitness News reporter David Ham that they have known about this problem for at least four years.

Bernardo Ruiz, Seattle Public Schools director for equity and race relations, told Ham that there has been more than one complaint, and the district has been trying to fix the problem.

"We agree that we have an issue with (the figures) being disproportionate," Ruiz said, adding that the district has created several task forces and committees to address the problem.

Natalie Davis told Ham that the problem at Seattle Public Schools was so bad for her son in kindergarten that she moved to Bellevue to put him in another district.

"I was really confused about a lot of incidents that were happening with my son," Davis said. "He was disciplined every day,"

She said that now that her son is in a different district, he doesn't have discipline issues.