The police said they had filed a first information report against the Uttar Pradesh State Bridge Corporation's Pariyojana Prabandhak in February for obstructing the road. "But it is we who have been alerting them about the potential problem and they have not acted".

India has a long history of construction accidents caused by poor materials and inadequately trained workers. The cases have been filed under sections of negligence and culpable homicide not amounting to murder. The FIR was registered at Sigra police station against supervising officials, contractors and staff involved in the construction of the flyover.

The corporation's director, Rajan Mittal, however said that the firm had requested local authorities including the district administration, police and commissioner to regulate traffic in that area during the construction.

A huge concrete slab slammed down onto the crowded road below, crushing at least four cars, a motorcycle and a bus.

Late Tuesday night, Deputy Chief Minister Keshav Prasad Maurya suspended four UPSBC officials - chief project manager H C Tiwari, project manager K R Sudan, assistant engineer Rajesh Singh and engineer Lal Chand.

More people were feared trapped after the collapse in the city of Varanasi.The slab appeared to be at least 15 metres long and two metres wide.

According to DIG (law and order) Praveen Kumar Tripathi, all these allied aspects like diversion of route and maintaining security norms are the responsibility of the organisation which executes work there.

District Magistrate Yogeshwar Ram Mishra refuted Mittal's claims. "It is wrong to say that they had written to us". However, the district police maintain that they have not been told about the route diversion.

Meanwhile an FIR was registered yesterday against the state bridge corporation officials.

The committee has already inspected the site and collected the samples which have been sent to IIT Roorkee, for investigation.