The remains of seven people are expected to arrive in El Salvador on Saturday, while the bodies of eleven Guatemalans will be flown home next week. The body of a victim from Colombia has already been flown home.
In the next week, fingerprint experts will arrive from Venezuela to identify additional victims, while relatives of six Venezuelans killed will identify their family members.
The fire at the migrant detention center in the city of Ciudad Juárez, on the border with the United States, is believed to have started when some of the migrants set fire to mattresses in protest that they had been deprived of their liberty.
Surveillance footage appears to show guards leaving the warehouse as the mattresses catch fire, with no apparent attempt to let the men out. Three employees of the migration authorities and a private security guard have been arrested in the murder investigation after the fire.
In the fire, 40 people died and 14 were seriously injured.