Police said the robbery occurred on July 6 when two persons carrying the cash were coming from Salem.
In their complaint, the duo said they were waylaid, assaulted and relieved of the money by a gang, which also took away their vehicle near Thennampalayam.
The car was found abandoned in Palladam in nearby Tirupur district.
A special team formed to investigate the case arrested six persons and recovered Rs 17 lakh, some weapons and seven vehicles they were using, Superintendent of Police, M Sudhakar, said in a release here.
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All of them were produced before the court and remanded to custody.
The gang was reportedly involved in similar cases in Malappuram and Thrissur in Kerala.
The seized amount was suspected to be Hawala money and would be handed over to IT department, Sudhakar said.
Police are on the lookout for some more accomplices involved in the case, he said.