The incident took place when a bank's cash van was about to leave an ATM site for reloading the cash in another ATM, they said.
Four unknown assailants came on car suddenly and placed a pistol on the head of Deepak Kumar, the cash incharge and then snatched the trunk containing Rs 50 lakh, police said, adding, all of them fled from the spot.
The cash belonged to State Bank of Patiala, police said.
Kapurthala SSP Dhanpreet Kaur and other senior officers visited the crime scene to take stock of the situation.
On December 12, jewellery worth Rs 25 lakh was looted at gun point by four unidentified armed miscreants from a shop in the same locality and nobody has been arrested so far.