Cobb Superintendent Fred Sanderson apologized Thursday to school board members who didn't know the principal they named to lead North Cobb High had been investigated on sexual harassment charges.

Some board members said they were not told about a seven-month internal investigation into allegations against Lawrence Bynum, former principal at Floyd Middle School .

"I was not aware that there was an investigation," said board member John Abraham whose district includes North Cobb High. "It wasn't brought to our attention."

Board member Lindsey Tippins also said the board was unaware of the investigation when it approved Bynum's appointment in June.

Bynum could not be reached for comment Thursday afternoon.

A teacher at Floyd Middle filed a complaint with the school district against Bynum earlier this year charging sexual harrassment and intimidation and violation of the school system's equal employment policies.

An investigation by the school system's human resources department found insufficient evidence to support the sexual harrassment charges by the unnamed teacher.

However, the in-house investigation concluded that Bynum did violate equal opportunity employment practices. That drew a letter a reprimand, said school system spokesman Jay Dillon.

In his letter of apology, Sanderson stood by his recommendation of Bynum to lead North Cobb High, describing him as "a dynamic leader whose no-nonsense approach may, at times, draw criticism. But his record of success is undeniable."

At the same time, Sanderson said he has "real concerns" about how the internal investigation was handled. He called for an external review of the school system's investigation process and whether is violated district protocol.

Dillon said the teacher who had filed the complaint has since been transferred to Lindley Middle School.