The 'correspondent' (administrator) is the sixth person to be arrested in the case, police said.
Five persons, including the Physical Education Director of the Padma Seshadri Bala Bhawan at K K Nagar, have been arrested.
The deceased, identified as Ranjan, son of a Tamil film director, had drowned during his swimming period yesterday.
His trainers noticed him in an unconscious state after which they rushed him to a nearby hospital where he was declared brought dead, police said.