A five-member van-borne gang had intercepted the Kerala-bound car on pretext of carrying out a search.
Two of the three Tamil Nadu police personnel wanted in connection with a Rs 3.90 crore highway robbery from a Kerala-bound car last month, were nabbed near Karur on Thursday, police said.
A police inspector allegedly involved in the case was arrested recently.
Police said they received information that the two police personnel, an inspector and a head constable, had tried in vain to file anticipatory bail petitions at a court in Madurai.
They later received a tip-off that the two were near Karur, following which they were arrested and brought to Coimbatore early on Thursday morning for questioning, police said.
On August 25, a five-member van-borne gang, including three dressed as policemen, had intercepted the Kerala-bound car on the pretext of carrying out a search.
They had ordered the four occupants to get into the van and two of their accomplices followed the vehicle in the car.
At a major road junction, they were forced to get out and the gang escaped with the cash and car, which was later found abandoned at Thrissur in Kerala.
Police said their probe led to the arrest of three persons, who revealed the hand of the police personnel in the robbery.
The trio also said that Rs 2 crore cash was taken by police and the balance distributed among them.