Sanjeev (25) broke into an ATM of the Punjab National Bank and looted around Rs 3 lakh from it last night, they said.
He threatened the security guard with a screw driver and tried to escape with the loot on a motorcycle driven by his accomplice identified as Raghav.
The accused was nabbed by patrolling officers when the security guard raised an alarm, police said.
"Raghav fled the spot when the guard raised the alarm, while Sanjeev was caught trying to escape with the loot on foot," said Ajay Kumar, Deputy Commissioner of Police, East District.
Rs 2.68 lakh, an uniform of a security guard and a few screwdrivers were recovered from the accused, while the search for his accomplice is on, he said.
Sanjeev who worked as a cash feeder in ATMs was an expert in the functioning of the machines and knew how to unlock them, the police official said.
"During interrogation he has admitted to have stolen cash from ATM of the same bank across the city earlier" said Kumar.