Djouma Bah – who was a social sciences student – had allegedly been caught using his phone during Guinea’s national school-leaving baccalaureate on 15 July, when he was arrested with other students, also suspected of exam fraud.
Two days later, he was convicted for cheating and sentenced to six months in prison, five of which were suspended.
He was serving his one month in a prison in the city of Kindia, about 137km (85 miles) north-east of the capital, Conakry, when his health deteriorated.
The teenager was subsequently transferred to the regional hospital for treatment.
Saliou Bah told the BBC that when he visited his son in hospital, the boy said he could not breathe properly and asked to lean against him.
“Then he looked at me and said: ‘Dad, I’m dying,'” Saliou Bah said.
“Those were his last words.”
The teenager spent around two days in hospital before being discharged to go home, where he died, according to officials.
Education Minister Alpha Bacar Barry said he was “deeply saddened by the news” and extended his “sincere condolences” to the family.
Human rights organisations are also calling for an independent investigation into the circumstances surrounding his death and the prosecution of other students.
On Wednesday, students demonstrated over the detentions of their fellow classmates, calling for their release.
“A student should not be sent to prison. These young people are the future of our country,” Saliou Bah said.
“I also ask the authorities to release the other students who are still detained before they too lose their lives.
“We lost our son; we lost our future.”
