During a brief interaction with media yesterday, the girls maintained that they took the extreme step due to "harassment and ragging by seniors".
They said though they had brought the matter to the notice of authorities, no action was taken.
They also gave statement about it to National Human Right Commission acting Chairperson Justice Cyriac Joseph, who visited the girls and SAI centre yesterday.
Joseph told reporters that the police investigation in the incident was on the right direction.
The four consumed a poisonous fruit on May seven and Aparna died the next day. The other three were undergoing treatment and counselling since then.
The incident had triggered widespread protest from different quarters and parents of the girls had demanded a CBI probe into the matter.