Rs 85 lakh was seized in Dibrugarh on Wednesday that led to four persons being detained in this connection, police said.
The Central Industrial Security Force (CISF) personnel recovered the cash that was transported by a Delhi bound flight, Dibrugarh Superintendent of Police Pratik Thubey informed.
The four detained were travelling from Arunachal by road and were enroute Delhi.
"The detained persons and the seized cash will be handed over to the Income Tax department for further investigation," Thubey said.
The interrogation is underway but the detainees have claimed that the amount was given to them by their business partner at Khonsa in Arunachal, the police officer said.