Four members of the same family on their first holiday to Goa were among the 25 killed in a deadly fire at a nightclub in the popular Indian tourist state on Saturday night.

The massive blaze broke out at just before midnight at Birch by Romeo Lane, a buzzing bar, restaurant and nightclub in north Goa’s Aporna district.

Most of the hundreds of guests inside the venue were able to escape but 20 members of staff – mostly working in the kitchen area – were killed after they were trapped in the basement and suffocated to death.

Officials said the venue had contravened multiple safety regulations and that the basement had no fire safety exit. The venue’s general manager, as well as the owners and event organisers, were all arrested and charged by police on Sunday.

Five Indian tourists, from Delhi and the state of Karnataka, were also named among the dead. They included the four family members, three sisters and one of their husbands, who had travelled from Delhi for a holiday and had just finished up eating dinner at the club.

Speaking to the Hindustan Times, family friend Harish Singh said that as the fire broke out and people began to panic, the family realised one of their sisters was still inside and rushed back to save her.

“The sisters rushed inside, followed by Vinod to save their kin. Everyone was running around and some people were stuck in kitchen,” Singh said. “The family tried to escape but couldn’t come out as everyone was pushing each other and there were no proper exits.”

Only one of the four sisters had survived. “They were all very excited for the trip, it was their first trip to Goa,” Singh said.

According to a technical evaluation of the incident, the venue – which was largely made of highly flammable wood and bamboo – had violated multiple safety regulations, including hosting a live music show that had pyrotechnics at the time the blaze broke out.

Investigators are still determining if sparks from the show’s fireworks caused the fire, or if it was faulty electrics or a short circuit which set it off.

“Prima facie observations indicate possible short-circuiting in electrical systems located above the main stage, supported by combustible internal furnishings,” the initial report said.

The emergency response was also hampered by the narrow lanes to access the nightclub, which had promoted itself as an “island venue” in inland north Goa.

The state government has also formed a high-level committee to inquire into the incident, and the report will be submitted within a week.