Surat police seized Rs 76 lakh in new Rs 2,000 currency notes from four people on Friday.
Based on specific tip off, the police intercepted a Maharashtra-registered Honda City (MH15 EP 4455) and recovered 3,800 notes of Rs 2,000 denomination from the boot of the car.
Surat income tax department officials will carry out a detailed probe.
Two of the detained were from Gujarat - identified as Girish Patel of Valsad and Dipti Patel, reportedly a fashion designer from Chikhli in Navsari district. The other two -- Rajkumar Singh and Arun Kashinath Amutar -- belonged to Nashik.
Police sources said the cash was brought from Nashik and it was likely to be delivered to a person in Sachin GIDC area.