Tegucigalpa, Honduras (CNN) -- The death toll from a prison fire in central Honduras rose to 382 Thursday, as new details emerged about what happened when flames tore through the overcrowded facility.
Officials transported bodies from the prison in Comayagua to the capital, Tegucigalpa, where investigators worked to identify the victims. The cause of the fire remained unknown, and the federal government asked for patience during its inquiry.
But desperate families said they didn't want to wait to recover the remains of their loved ones.
"What we are hoping for is that they give them to us so we can leave because we cannot stand the hunger, too," said Francisca Gomez, the sister of one of the victims. "We have our children with us and you know that we've been here waiting and no one gives us answers."
The Comayagua fire department gave the new death toll, and said that it remained unknown if others escaped or would be added to the casualty list.
The hypothesis that a mattress fire started the blaze was gaining traction, fire operations chief Jorge Turcios said Thursday.
Comayagua's governor said she received a call from an inmate inside the prison reporting the fire.
"What I know, according to what I've been told, is that someone lit a mattress on fire and said, 'We're all going to die,'" Gov. Paola Castro said.
Inmates have also complained that guards were slow to open doors for them to escape. Prisoners broke out of the facility any way they could, one survivor said.
"The authorities should have opened the gates," said Odalis Aleyda Najera, a relative of a victim. "It is preferable to face the responsibility for a mass escape of prisoners and avoid situations like this where there are more than 300 dead inmates."
Outrage over the fire increased after the president of the country's supreme court admitted that only 40% of the inmates in the prison had been convicted. The majority were awaiting trial or waiting for charges to be filed against them.
"Honduras passed an anti-gang law, and what it allowed police to do is to sweep anybody off the streets ... who they had a suspicion was a member of a gang, but really had no proof. So the prison population swelled," said Vikki Gass of the Washington Office on Latin America. "And so in the case of Comayagua, you don't have enough magistrates or judges to process the people who are being detained."
Authorities have not determined what caused the fire, but the nation's electric utility will review wiring in all prison facilities as a "preventative measure," Honduran President Porfirio Lobo said, "because that can be one of the causes of these types of disasters."
The prison facility was well over capacity, said Rodrigo Escobar Gil of the Inter-American Commission on Human Rights.
"The prisoners slept on the floor and they had to share cells in truly deplorable conditions," he said.
At the request of Honduran officials, arson experts from the United States were expected to arrive in Honduras Thursday to lend a hand, Turcios said.
The team from the U.S. Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) will reconstruct the scene, conduct interviews and sift through debris to obtain evidence and determine the origin of the blaze, the agency said in a statement.
Teams from El Salvador, Chile and Mexico were also expected to help Honduran authorities.
Tuesday night's blaze was the third fatal prison fire in recent years in the country. In 2003, 61 prisoners were killed in a fire at a prison in La Ceiba. In 2004, 107 died in a fire at a San Pedro Sula prison.
The U.S. State Department published a report last April criticizing conditions at Honduras' 24 prisons.
Prisoners "suffered from severe overcrowding, malnutrition, and lack of adequate sanitation," the report said, citing human rights groups.
CNN's Carol Cratty, Brooke Baldwin and Camilo Egana contributed to this report.