Though the robbery was discovered on Monday morning, police said the gang committed the crime between Saturday night and early Monday.
The audacious robbery was one of the biggest in the country in recent times and matched the sensational Chelambra bank robbery in Malappuram district of Kerala in 2007.
Gohana is in Sonepat district and around 200 km from capital Chandigarh.
The 2.5 feet width tunnel was dug from an abandoned building located across a lane of the Punjab National Bank branch at the old bus stand locality of the town. Police found two rooms in the abandoned building filled with earth removed from the tunnel.
The robbers had also blocked the building’s windows with cardboard to hide their activities from the outside world.
Police said that the crime was planned and executed over many days, probably stretching for more a month.
Gohana deputy superintendent of police Rajeev Deshwal said they were studying CCTV footage in the bank to indentify suspicious persons in the past few weeks. Banks, however, do not install CCTV cameras inside strong rooms.
With news of the heist becoming the talk of the town, people flocked the PNB branch throughout the day though no one was allowed inside by police.
In the Chelambra bank robbery too, robbers had drilled through the floor of the South Malabar Gramin Bank – located on the second floor of a building – to enter the strong room and loot 80 kilograms of gold and cash, the value of which was estimated to be Rs. 80 million.
The kingpin had confessed to have been inspired by the Hrithik Roshan-starrer Dhoom which featured a similar heist by drilling through the floor of a bank.