GUATEMALAN coroners are investigating whether the 40 girls killed at an abuse-riddled care home last week had been drugged and doused with fuel.

National Institute of Forensic Sciences director Nery Cabrera told the congress governing commission on Monday that the evidence strongly suggested mass murder, Guatemalan daily Prensa Libre reported.

That backed accounts by firefighters, staff and young survivors of last Wednesday’s horrific blaze at the Virgen de la Asuncion safe home south-east of Guatemala City.

Mr Cabrera’s submission to MPs came as prosecutors said former social welfare secretary Carlos Rodas, who resigned on Saturday, his deputy Anahi Keller and care-home director Santos Torres had been arrested on suspicion of homicide, mistreatment of minors and failure to fulfil their duty.

Earlier in the day President Jimmy Morales said he had fired the chain of command at the Social Welfare Secretariat but did not specify how many employees were dismissed.

Mr Cabrera said the victims’ extensive burns — over 75 to 90 per cent of their bodies — suggested they had been doused with petrol or other fuel.

He said his agency was testing the victim’s bodies for traces of sedatives and other drugs.

Mr Cabrera said the dead girls were still wearing their pyjamas when the fire broke out at 9am, “which says they were sleeping.”

He added that the ceiling of the dormitory was completely burnt and the heat of the blaze had been so intense that it had stripped the paint from the doors and the metal bars.

Autopsies showed 20 victims died of asphyxiation by fumes above 100°C and 17 of burns.

Mr Cabrera stressed: “Nobody was left alive after two minutes.”

Mr Cabrera’s statement contradicted claims by the home and Mr Rodas that the girls had set their own mattresses alight.

The victims had been locked in after trying to escape the overcrowded home on Tuesday night after over-18s from the home’s young offenders’ section had invaded the girls’ dormitories.

The home, designed for 500 children, held a mixture of 800 orphans, children with mild disabilities, victims of familial abuse and young offenders.

Relatives say children told them the home was rife with sexual abuse that included the production of child pornography, drug dealing, forced labour, short rations, rotten food and other shocking mistreatment.

Guatemala’s human rights prosecutor Jorge de Leon said his agency had asked a judge to review conditions at the home before the fire, but the request was denied.

On Saturday four survivors with very severe burns were flown to a US children’s hospital in Galveston, Texas.