Fire Lt. Charlie Thomason has stepped down as president of the Chattanooga Fire and Police Pension Fund after two years amid an internal affairs investigation by the Chattanooga Fire Department.

Thomason, who has been on the board of the pension fund since 2015, asked to resign from his role as president but remain on the board during Thursday's regular board meeting, according to fund administrator Katrina Abbott. While the lieutenant cited health concerns for his resignation, he was placed on administrative leave by the fire department in late December while the department conducts an internal investigation into him.

"Lt. Charlie Thomason is on paid administrative leave pending an investigation by CFD Internal Affairs. No further details will be released until completion of the investigative process," Chattanooga fire spokeswoman Lindsey Rogers said in an email Friday.