Police on Wednesday said the cash van carrying Union Bank of India’s Rs 1 crore deviated from its set route for the first time since it has been frequenting Jamui for money transfers.

“The driver and the two guards are being questioned. The cash vehicle that travelled to Jamui frequently always took National Highway-30. But on Tuesday, the driver deviated and took the under-construction road for the first time. On the same day, the criminals were waiting for the van. This clearly hints at a plan to be executed and the change of the path was deliberate,” Patna senior superintendent of police (SSP) Manu Maharaaj said.

From interrogation of suspects, the inquiry into the Union Bank of India’s Rs 1 crore loot has now shifted to the technical aspect.

A day after the loot, the police shortlisted five gangs, which could be behind the heist. Though nothing concrete cropped up against the driver of the cash transfer vehicle and the two private security guards, the police still believe that the three men could hold the key to the investigation. This is primarily why they have still been detained.

Maharaaj said: “Our hands are empty. The police stations have been asked to carry out extensive patrolling and vehicle checks. We need to identify the gang responsible and work on the leads. Five gangs operating in and around Patna are under the scanner. We are trying to get information about their locations and movements with the help of technology and other scientific methods. The big question still remains as to how did the men know the exact location of the cash transfer van.”

On Tuesday, a cash van of a private security agency, on its way from Patna to Jamui with Rs 1 crore belonging to Union Bank of India, was looted on an under-construction four-lane road near Fatuha, around 20km from the state capital.

He said the police need to carry on with more detailed investigations to ascertain the role of an insider. “The driver and the guards are under the scanner but others could be involved too. What is also surprising is the fact that among the seven steel trunks in the van, the criminals knew which trunk had the money. The versions of the driver and the guards are differing which raises doubts. It also seems strange that the two guards didn’t react when the men surrounded the vehicle,” the SSP said.

Sources said the police were concentrating on two gangs — the Prem Sahni gang and the Sonu gang. “These two gangs are active in Patna and have looted banks earlier,” another police officer said.