"We have collected some materials, tested them and found flaws there. We have to collect more samples and test them," said Dr Sekender Ali, the chief of the five-member probe committee that met on Thursday to outline the probe procedures.

The ground floor of the under-construction building subsided and a part of it collapsed on May 25 midnight, raising question about the quality of DCC's development works.

It will take around one month to submit the complete report although the DCC mayor on the day after the accident asked the probe committee to submit their report within one week, Sekender Ali told The Daily Star yesterday.

The members of the probe committee would visit the accident spot today for checking the design and conducting a soil test.

"If we cannot conduct the soil test today we have to wait until the whole building is knocked down," said Dr Sekender.

The probe committee will also try to find out whether there was any misdeal during the tender process for the building.

They might start interviewing people relating to the construction including contractors, engineers of the DCC from next Tuesday, sources said.

Meanwhile the contractor of the work, Atikullah Khoka, who is now absconding, recently said over telephone that he would come in public if the probe committee report goes in his favour.

Meanwhile DCC staffs are still staying at the adjacent five-storeyed building that developed cracks due to the 'forced vibration' by the collapse of the under-construction building.

"We will check that building also. As cracks have developed at the building, it needs to be strengthened," Dr Sekender said.