A staff member at Ralston High School has tested positive for COVID-19, according to district spokesman Jim Frederick.
Officials with the Ralston Public Schools received confirmation Monday afternoon, Frederick said.
The staff member began having symptoms on March 16, he said.
Classes were not in session at the time. Students were last in the building on March 12.
The district has been closed to students since then.
On March 13, the district announced it was closing as a general precautionary measure, not related to this case, through March 21. Then, last Thursday, community spread in Douglas County prompted the governor to order that schools in four metro Omaha counties, including Ralston schools, close to students for six weeks.
In a letter Monday to families of students, district officials said Douglas County Health Department officials believe no Ralston High School students are at risk because school has not been in session.
The employee had direct contact with a limited number of staff members in only certain areas of the school, district officials said.
Those employees have been notified.
A small number of employees who were at the school on March 16 and 17 are at little to no risk of contracting the disease, the district said.
"We understand the concern a possible exposure causes," the district said. "Our custodial staff has gone back through and deep cleaned the entire school."