Rambhai Bhilariya, 27, the victim, worked at HDFC bank's Keshod branch, police said.
Bhilariya and his colleague Kishor had struck a deal with the accused Bhikhubhai to exchange latter's defunct currency notes for commission, said inspector A V Tilva.
"Bhilariya and Kishor had told some persons that they can exchange defunct notes with new notes on 20 per cent commission," said the police officer.
Bhikhubhai asked Bhilariya and Kishor to come to Magarwada village near the town in the afternoon with Rs 9 lakh in new currency.
"When the two reached there, Bhikhubhai and three others argued with them over some issue, and snatched the bag containing Rs 9 lakh and ran away. When Bhilariya tried to stop them, Bhikhubhai stabbed him with a knife. Kishor was also injured in the attack," said the officer.
"Bhilariya died while Kishor is admitted to a hospital. We have lodged a case of murder with robbery," inspector Tilva said, adding that search was on for the accused.