At least 43 workers died in the factory, which made school bags and toys, in New Delhi’s deadliest fire in 20 years.

Police in New Delhi have arrested the owner and manager at a factory where 43 people were killed in the Indian capital’s deadliest fire in 20 years, a spokesman said on Monday.

The blaze started early on Sunday morning when more than 100 workers were sleeping in the four-storey building located in a residential part of the city.

The factory – which made school bags and toys, according to Indian media – was packed with combustible materials like paper, plastic and cardboard, causing it to burn for hours before the fire was brought under control.

“We have arrested the owner and a manager of the factory where the fire broke out and initiated an investigation which is going to be completed soon,” Mandeep Singh Randhawa, Delhi police spokesman, told Reuters news agency.

Most of the victims of Sunday’s fire were migrant workers from the impoverished eastern state of Bihar, earning as little as 150 rupees ($2) a day and sleeping at the factory between lengthy shifts.

The Indian Express carried a quote from one of the victims who had telephoned a neighbour in his hometown in central India, saying he was trapped and would die soon and asking the neighbour to take care of his family.

Fire engines had struggled to access the congested lane where the building was located, witnesses said.

Frequent raids by civic authorities to enforce building codes, fire safety measures and evacuation procedures have failed to curb violations in the rapidly expanding city of about 20 million people.

Delhi Chief Minister Arvind Kejriwal announced a compensation of 1 million rupees ($13,933) for the families of those killed.

On Monday morning, more fire engines were dispatched to the factory to douse a small fire caused by burning waste.