Philippine officials say 72 people are now confirmed dead after a fire tore through a slipper factory in an impoverished section of Manila.
Dozens of people were also injured when the fire broke out at the Kentex Manufacturing Company, which produces locally sold rubber slippers.
It is not clear how many people, if any, remain missing.
The blaze at the two-story building is believed to have been started by welders whose equipment came in contact with chemicals.
"While we were welding, there was a spark and the fire spread. We tried throwing water and using the fire extinguisher, but it didn't work," said Steve Chua, a factory worker.
Many of the victims' families are upset over what they say are the factory's lax fire safety standards. Many workers said they had not participated in fire drills. It is also unclear whether the factory had the required number of fire escapes.
As forensic officers worked to identify the dead and reconcile their names with those listed as missing, questions were being raised if the factory followed fire and building safety standards.
Metal bars and metal caging covered many of the building's windows, preventing the workers from escaping. The bodies of those trapped inside were said to be completely burned to the bone.
Dionesio Candido, whose daughter, granddaughter, sister-in-law and niece were among the missing, said the iron grills reinforced with fencing wire covered windows on the second floor “could prevent even cats from escaping.”
He said he was allowed by authorities to enter the gutted building, where he saw charred remains “piled on top of each other.”
Local media reports quoted relatives as saying their kin sent frantic text messages asking for help from second floor, but contact was lost shortly after.
Officials are still investigating, but Philippines National Police Chief Leonardo Espina told reporters Thursday that "for sure someone will be charged" with a crime.
Valenzuela city fire marshal Mel Jose Lagan said arson investigators will look into why the people were unable to escape from the second floor when there was a “sufficient exit” that includes a wide stairway to the back of the building leading to the outside. They will also look into whether there were more people inside the building than allowed.
Iron grill bars on windows are common in offices, factories and homes in the Philippines to keep away thieves. In workplaces or factories, they are also meant to prevent employees from stealing equipment or products.
Valenzuela Mayor Rex Gatchalian said that a workers log book was lost in the fire and the foreman was among the dead, making it difficult to determine how many were inside the factory at the time.
The chief of the national police medical examiner's office, Emmanuel Aranas, said fingerprints could no longer be used to identify the burnt victims and forensic officers will have to rely on dental records, DNA and personal items to identify the bodies.
Some material for this report came from the Associated Press.