Workers around 3:15 p.m. today pulled down the exterior wall of Baker High School's fire-gutted south wing so investigators safely could get into the building.
Investigators said the wall had been too unstable to risk going into the burned wing.
Fire Marshal Thomas Streeter, a 1982 Baker graduate, said the wing that burned had housed the school's ROTC class, wood shop, home economics, chemistry class, an armory and a school radio station, WBHS.
He said that wing was the only part of the school complex damaged by the fire, though other buildings have deteriorated or been vandalized.
Deputy Chief Jerry Fountain said firefighters had two advantages in containing the fire to that building: No strong winds fanned the flames, and recent infrastructure improvements with development north of the school enabled the Columbus Water Works to increase water pressure to fire units battling the blaze.