The principal of North View Secondary School said Benjamin Lim appeared calm when the 14-year-old arrived at his office.
Speaking in court on Tuesday (May 17) at a coroner's inquiry into Benjamin's death, Mr Chen Fook Pang said the young boy "cooperated very well" and did not look anxious throughout when talking to Police Inspector Poh Wee Teck.
He was able to respond well to the inspector's questions, said Mr Chen.
The school's counsellor, Madam Karry Lung, added when she took the stand that Benjamin was coping well during the interview.
She had not deemed it necessary to intervene.
But the young boy became fidgety after calling his mother before leaving for the police station, the principal noted.
Mr Chen had earlier asked the police if Benjamin could call his mother and the boy did, before passing the phone over to Insp Poh.
Insp Poh told the boy's mother in Mandarin that police needed to bring him back to Ang Mo Kio Police Division to assist with investigations, and that someone would inform Mrs Lim later on how to pick her son up.
The phone was passed back to Benjamin.
"At this point, I could hear Benjamin's mother speaking very loudly, even though the phone was not on speaker mode," added Mr Chen, who said he could not make out what was being said.
This was a view shared by Madam Lung.
"I noticed that he started frowning, and his replies became softer," she said. Sensing that the conversation "was not doing him any good," she signalled non-verbally that the exchange should end.
Mr Chen noted that the boy appeared anxious after the phone call.
Before the police interviewed Benjamin, Mr Chen told the court that he made three requests to them.
He wanted to talk to Benjamin first, without officers present.
He also asked that only one officer, not five, speak to Benjamin, and requested that school staff be allowed to sit in during the interview.
On the purpose of his requests, Mr Chen said he had every right to speak to his student first, to check on the student's well-being. Doing so has been the school's "common understanding with the police".
He added that he had "pushed (his) luck a bit further" by requesting that school staff be present during the interview as well. This was not necessarily the case in previous cases, added Mr Chen.
He also said that five police officers was a "too big" a number to conduct an interview.