“This lapse proved fatal,” IG S N Pradhan had told The Indian Express the day the incident had occurred.

One of the survivors, BSF constable Pratap Singh, said they had boarded the bus because they were running short of time.

“We had got up at 2 am. At 4 am we were out with the poll staff. After escorting them for nearly six km on foot, we were on way back to the camp. Since we had to attend duty at a polling booth by 7 am, we were left with little time. This made us call for the bus,” he said.

Despite the problems faced by the security forces, most of the top brass said that the SOPs should be followed with better coordination to prevent casualty.

DGP V D Ram said: “We are trying to ensure that. We hope we succeed.”