The city police, investigating last week's major fire at Mantralaya, on Monday claimed to have made a substantial progress in the probe and recorded statements of 50 witnesses in this connection so far.
"We have made a substantial progress in the case and statements of 50 persons including the injured, the Mantralaya staff and private electricity maintenance people, were recorded," Joint Police Commissioner (Crime) Himanshu Roy said.
The crime branch was also seeking electrical engineers' help to understand how the fire spread, another officer said.
"The switch rack on the fourth floor, from where fire started, is being examined by the forensic experts. The process to retrieve the CCTV footages is also underway," he added.
The fire broke out exactly at 2.37 pm on the fateful day, police said adding that they did not come across any contradictory statements so far.A huge fire had broken out at Mantralaya on Thursday, gutting large parts of the 7-storey building including offices of several ministers and claimed five lives.