The parents said last night that they had been told that the toilet door handles had been removed for repair. He was also unsupervised at the time..
Mr Banerjee said he was told of an incident months prior to Aryan's accident in which another student had to crawl under the toilet door to get out.
"There are so many ways this could have been avoided and so many questions that need to be asked.
The Banerjees were yet to receive a "formal apology or explanation".
The parents recalled the tragic moment they learnt of their son's fate. "I just froze," Mr Banerjee said.
"His eyes were open but he wasn't seeing."
They said his whole body was giving way.
"He was slowly dying."
Mrs Banerjee said her son was a "delightful boy" .
"He had a very dry sense of humour, was good to his friends and would stand up to bullies."
Back in September Mr Banerjee told Hawke's Bay Today: "You should never outlive your kids".
"He was a fun-loving child who was friendly and wanted to play with everyone and anyone."
Aryan was taken back to his ancestral homeland where his ashes were sprinkled in the Ganges River.
Aryan's 11-year-old brother, Anshul told the television programme that he dearly misses his little brother and tries his best to "keep it in".
"I miss his general happiness, he was always smiling."
Sunday said last night that Principal Marty Hantz had told it he was unable to comment while the investigation was still under way.
Attempts by Hawke's Bay Today to contact Mr Hantz proved unsucessful.
