The accident happened in the early hours of Saturday (27).
In total, 58 injured people were rescued and four deaths have already been confirmed.
The vessel Comandante Souza III left the Port of Manaus and was on its way to the municipality of Santa Isabel do Rio Negro, in the interior of the state.
The boat caught fire near the Santa Maria Community, which is 40 minutes from the capital of Amazonas.
By the end of Sunday (28), the Legal Medical Institute (IML) confirmed four deaths as a result of the tragedy.
The victims were identified as;
Flora de Oliveira Olar, 76 years old; Clotilde Cordovil Venâncio, 65 years old; Zita Plácido Melgueiro, 51 years old; and Sirene Dias Oliveira, 72 years old.
The Amazonas State Secretary of Health (SES-AM) reported that five people remain hospitalized in health units.
Five people remain missing according to a statement released by the Brazilian Navy on Sunday morning(28).
The number however, may change due to the fact that the only passenger list was burned during the fire.
The causes of the fire are still unknown to authorities. An examination should be carried out by the Amazonas Military Fire Brigade (CBMAM) in conjunction with the Brazilian Navy, in the coming days.
According to witnesses, the flames spread quickly, which caused the machinery to stop functioning.
Because of this, the lights were turned off and the entire vessel was left in complete darkness.
At the time, the passengers, unaware of what was happening, ended up panicking.
To save themselves, people threw themselves into the river.
A By means of a note, the Brazilian Navy informed that it continues the search for missing people this Monday (29).
The Government of Amazonas stated that rescue teams from the Fire Department continue to work at the scene of the fire in search of possible missing people.
The city hall of Santa Isabel do Rio Negro issued a note declaring three days of official mourning throughout the municipal territory as a sign of condolence.

Source: Amazon Agency