The fire brigade on Saturday asked for CCTV footage and records of drills conducted at Acropolis from the authorities and said the mall will remain closed till their inspection was completed.

All 99 offices and 115 stores in the building will remain closed, a senior fire officer said. It could take up to a fortnight for the mall to be reopened, he added.

The CCTV footage will help determine the origin of the fire, the movement of the smoke inside and how the firefighting systems fared.

Employees of several stores were allowed to go inside on Saturday and check their stores. Some of them also took away perishable goods and merchandise from their stores.

One or two employees of all offices that ran from the building were also allowed to go inside in turns and check their workplaces. Several employees of offices said they would return on Monday for a clearer picture on when they can resume working from the building.

The fire brigade and forensic officials visited the mall on Saturday.

Senior officers of the fire brigade also held a meeting with the mall authorities in presence of the CESC, the power supplier.

A large portion of the ceiling of the mall’s third floor has been gutted. The manager of the store of a clothing retail company said that soot marks were widespread on the ceiling of the second floor, too. Even the first floor ceiling had sagged in many places because the water used to douse the flames had flowed into the ceiling.

“We have asked the mall authorities to provide us with footage of all CCTVs for 24 hours (between Thursday midnight and Friday midnight). This will tell how the fire broke out, the path of the smoke and what systems worked and what did not work,” Jag Mohan, director general of West Bengal Fire and Emergency Services, said on Saturday after visiting the mall.

“We have asked the mall to give us records of their drills. We want to see if regular fire drills and evacuation drills were held. All high-risk buildings (like malls) are supposed to have technically qualified people to run the firefighting systems. We have sought a list of those people employed by the mall, what their first responses were after the fire broke out and how they helped in the evacuation” Jag Mohan added.

The fire brigade has also sought details of the renovation underway at the mall, including the precautionary measures they had taken.

A preliminary inspection by fire brigade officers suggested that an electrical renovation on the food court ceiling, just under the Crossword bookstore, may have caused sparks that led to the fire.

The exact cause will be ascertained only after the forensic report comes, fire brigade officers said.

When asked if the fire brigade will lodge any police complaint against the mall authorities, Jag Mohan said: “Let the forensic reports come. Let us also speak with our own people and hear their accounts.”

The mall authorities said they were cooperating with the fire brigade.

“We are cooperating with fire and forensic department and will furnish all data, documents and footage as asked by the department. As a responsible corporate, our aim is to normalise mall operations as soon as possible but without compromising with safety measures of our patrons, visitors employees, office staff and our guests,” said Krishna Jha, senior operations manager, Acropolis Mall.

Jag Mohan later told Metro that it seemed to him that it may take up to a fortnight for the mall to reopen.

“Considerable repairs will be needed. We will also check if all systems are running properly before we give a green signal for the mall to reopen,” he said,

Since Saturday morning, employees of several stores had assembled outside the mall.

Mainak Chowdhury, the manager of the store of a clothing retail company on the first floor, said he went into the mall but could not go inside his store because the electronic shutter of the store could not be opened as power supply had been cut off.

“Our store did not suffer any damage, but I could not open the shutter,” he said.

An employee at the Spencer’s store at Acropolis said “the part of the store where frozen foods were kept has suffered considerable damage”.