A fire which killed 19 people at a secondary school dormitory in Guyana was deliberately set by a student, according to an official.
The suspect - who is among the injured - was upset that her mobile phone was confiscated, investigators believe.
She had been disciplined by the dormitory administrator for having an affair "with an older man", national security adviser Gerald Gouveia was reported as saying.
The student allegedly threatened to torch the dorm and later set a fire in a bathroom area, he added.
The fire on Sunday claimed the lives of 18 indigenous girls aged 12 to 18 who were from remote villages served by the boarding school in the southwestern border town of Mahdia.
A five-year-old boy and son of the housemother - the woman in charge of the dormitory - was the final victim.
Most of the victims died after being trapped in the burning building, but fire crews managed to rescue others by smashing through one of the walls.
Nine people remain in a serious condition in hospital.
Mr Gouveia described how the fire spread through the dormitory which had been locked by the house mother to prevent the girls from sneaking out.
He explained how "she did this out of love" for the girls since many would "leave the building at night to socialise".
He added: "The house mother was asleep at the time inside the building but panicked and could not find the right keys to unlock the building from inside but she made it out.
"She also lost her five-year-old child in the fire."
Forensic work is to be conducted to identify some of those who died at the scene.
Meanwhile, Mr Goveia said the man who allegedly had the relationship with the suspect is expected to be charged with statutory rape due to her being underage.