The probe committee is insisting on quick demolition of the building, but the authorities concerned are very slow to respond, said a committee member preferring anonymity.

"We have taken interviews of some people and we have already got the soil test report, but we have to inspect the pilings of the building to complete our investigation. So, we will have to wait for the completion of the demolition work," he said.

On Tuesday, the five-member committee interviewed eight people, who were involved in the construction work, including Atiquallh Khan Khoka, the proprietor of 'Atiq Construction', which constructed the building.

The construction of the building was completed recently and it was supposed to be open for Dhaka City Corporation cleaners on June 3. But the northern part of the six-storey building sank into the ground on the night of May 25.

The mayor of Dhaka City Corporation at that time said that the probe report would be submitted within one week.

Dhaka City Corporation (DCC), which employed labourers to demolish the building after the subsidence, has now given the charge to Atiq Construction, which will start the demolition work today.

DCC Engineer Iqbal Habib said, "As Atiq Construction has not yet handed over the building to DCC, we have engaged it to do the demolition work and for this they will not get a single penny."

However, the DCC and the construction firm expressed different views on the timeframe of the demolition work.

According to DCC officials, the demolition can be done within 15 days, but Atiqullah Khan Khoka said it would take at least two months to complete the job.

A labourer named Azoo told this correspondent that the DCC had employed 12 to 15 labourers who were working with elementary tools, including hammers, chisels and crowbars, while the construction firm has employed 20 labourers.