• The fire on 5 March in Bangladesh left 15,000 Rohingya refugees homeless and gutted some 2,800 shelters.
• Militant groups had started the fire to "dominate" the camps, said the government official leading the probe.
The blaze which swept through the world's largest refugee camp last week was a "planned and purposeful act of sabotage," investigators say.
The fire on 5 March in Bangladesh left 15,000 Rohingya refugees homeless and gutted some 2,800 shelters.
Militant groups had started the fire to "dominate" the camps, said the government official leading the probe.
Fires had broken out in several places at once, proving it was planned, said Abu Safian.
There were no casualties. But the blaze ripped through homes and took down key infrastructure networks- schools, medical clinics and service points - in several districts in the Cox Bazaar camp.
The seven-person panel formed to investigate the fire, presented its report on Sunday after interviewing 150 eyewitnesses.
It recommended further investigation to identify the groups behind the incident.
The fire erupted at 14:30 local time (08:30 GMT) in Camp 11 of Cox Bazar in south-eastern Bangladesh, and was brought under control by evening, the report said.
Cox Bazar houses over one million refugees who fled from Myanmar following a military crackdown against the Rohingya ethnic minority.
They live in huts made of bamboo and thin plastic sheeting. Overcrowded and squalid, these refugee camps are vulnerable to fires. Initial reports from the Cox Bazar fire had suggested the flames had also spread quickly through gas cookers common in the camps.
Between January 2021 and December 2022, there were 222 fire incidents in the Rohingya camps including 60 cases of arson, according to a Bangladesh defence ministry report released last month.
In March 2021, at least 15 people were killed and some 50,000 displaced after a huge fire tore through a camp in the settlement.