SAN JOSE PINULA, Guatemala >> A blaze that killed at least 35 girls at a shelter for troubled youths erupted when some of them set fire to mattresses to protest rapes and other mistreatment at the badly overcrowded institution, the parent of one victim said Thursday.

Officials said they are still investigating who started the fire Wednesday at the long-criticized shelter on the outskirts of Guatemala’s capital. It houses troubled and abused boys and girls as well as juvenile offenders.

Nineteen victims were found dead at the scene, and 16 more succumbed one by one to their grisly injuries at hospitals in Guatemala City. Several more girls were fighting for their lives, some with severe burns over more than half their bodies.

The 35th death was announced by the General Hospital late Thursday while President Jimmy Morales called for a restructuring of the country’s youth shelter system, which houses some 1,500 children around the country, during a news conference. Outside the presidential palace, dozens of protesters gathered to demand answers.

The fire started when someone ignited mattresses in a dormitory that held girls who had been caught the day before during a mass breakout attempt, authorities said.

On Thursday, distraught parents haunted hospitals and the morgue, passing scraps of paper scrawled with the names of loved ones they hoped to find.

Geovany Castillo said his 15-year-old daughter Kimberly suffered burns on her face, arms and hands but survived. She was in a locked area where girls who took part in the escape attempt had been placed, he said.

“My daughter said the area was locked and that several girls broke down a door, and she survived because she put a wet sheet over herself,” Castillo said.

“She said the girls themselves set the fire,” he said, adding: “She said the girls told her that they had been raped and in protest they escaped, and that later, to protest, to get attention, they set fire to the mattresses.”

Another surviving 15-year-old girl said that male residents had apparently been able to enter at least some of the girls’ dormitories before the fire. She and others took refuge on a roof for fear of being attacked and saw the fire break out in a nearby building.

“I saw the smoke in the place,” she said. “It smelled like flesh.”

The state-run Virgin of the Assumption Safe House has long been the subject of complaints about abuse, inadequate food and crowded and unsanitary conditions behind its 30-foot wall. The shelter was built to hold 500 young residents but housed at least 800 at the time of the fire.

Guatemalan President Jimmy Morales issued a statement blaming the disaster on the courts for ignoring a request by his administration to transfer juvenile offenders out.

“Before the fire, the government had asked the appropriate authorities to immediately transfer youthful offenders to other detention centers, to avoid greater consequences,” the president’s office wrote.

“The government regrets the fact that those authorities did not heed that request in an opportune way, something which could have prevented the tragedy.”

Jorge de Leon, Guatemala’s human rights prosecutor, said in a statement that during the mass breakout the evening before the fire, at least 102 children who escaped had been located, but others managed to flee. He said younger children fled the shelter because they were being abused by older residents.

“According to what they say, the bigger kids have control and they attack them constantly,” de Leon said. “They also complain that food is scarce and of poor quality.”

In 2013, a 14-year-old girl was strangled by another resident, investigators said.

Authorities said DNA tests might be necessary to identity some remains. A doctor at one hospital asked parents waiting outside for information to come back with photographs, dental records and details about tattoos or other distinctive features.

Piedad Estrada, a street vendor, arrived with a photograph of her 16-year-old daughter. She said the teen was pregnant and had been at the shelter for nine days because she ran away from home.

Estrada searched at the hospitals and the morgue but got no information. She showed the photo to workers at one hospital, but they said they had five girls who were completely bandaged so they could not be sure.

“They only took her from me to burn her,” Estrada said. “I blame the state for what has happened.”