Four more officers of the Hyderabad-based construction company in-charge of building the Vivekanda Road flyover, a portion of which collapsed last week, were arrested on Monday.
IVRCL Director Operations Gopal Krishnamurthy, Deputy General Manager of Project Monitoring Cell S K Ratnam and senior engineers Shyamal Manna and Bidyut Manna were arrested after a long grilling session at the Kolkata police headquarters.
With these four, altogether eight persons of the company have been arrested in connection with Thursday's collapse which left 26 people dead and 90 injured.
A senior police officer said that a police team visited the company's head office in Hyderabad after the collapse and six IVRCL officers were served notice.
Of them, Krishnamurthy, Ratnam and Assistant vice-president of PMC, A N Dilip, arrived in the city and were questioned.
"Bidyut Manna and Shyamal Manna are senior engineers of the company who were present at the site that day when the casting of concrete was laid. Both were involved in direct supervision of the works conducted by the labourers that day," the officer said.
Earlier, IVRCL Assistant General Manager Mallikaarjun Rao, Assistant Manager Debjyoti Manjumdar, Structure Manager Pradip Kumar Saha and Project Manager Tanmoy Sil were arrested under IPC Sections 302 (murder), 307 (attempt to murder) and 120B (criminal conspiracy) and others.
The police have registered a case against the construction firm and sealed its office in the city.
Another Assistant vice-president of PMC, Ranajit Bhattacharjee, who was injured and now hospitalised after Thursday's mishap, is also under police scanner.
"Bhattacharjee was reporting to Ratnam... So we need to look into that also. Let him get out of the hospital. We will also look into his roles," the officer said.
The police also asked three KMDA officials to meet police officers investigating the case to examine their role in the project.
Asked whether the three could be arrested, the officer said,"We cannot say anything at this moment. It depends... We are looking for answers of certain specific questions."