A local corporator, senior municipal corporation officer and policeman figured among the seven arrested by the police on Sunday for the building collapse in Thane, where 74 persons were killed and more than 62 injured.
The seven included a building materials supplier and an estate agent also. Earlier the developers of the building had been nabbed.
"The interrogation of the arrested developers has given us leads about the involvement of public servants who had been bribed to allow the illegal construction and we have documents to establish it. We have seized R5 lakh in cash from the residence of Deepak Sharadrao Chavan (deputy municipal commissioner) along with many incriminating documents," said KP Raghuvanshi, commissioner of police, Thane.
Raghuvanshi said the investigation had shown that money had changed hands.
"We will initiate action against people, irrespective of whether they are public servants or not," Raghuvanshi said, hinting at more arrests in the case.
He said the anti-corruption bureau (ACB) had been roped in to assist in investigation.
All the accused were produced before a holiday court on Sunday and were remanded in police custody for 14 days.
When asked about allegations that the police did not give protection to the civic staff during the demolition of illegal constructions in Thane, Raghuvanshi said the police had been giving protection to the municipal authorities every alternate day and 167 illegal structures were brought down in Thane last year.