Six people were arrested on Monday for travelling in a defence ministry vehicle without valid documents in West Bengal's Burdwan district, police said.
The car bearing a plate with the words "Government of India Ministry of Defence - OFB (Ordinance Factory Board) Kolkata" was seized by police and six of its occupants arrested in the early hours of the day on the national highway 2 in Jamalpur.
"All of them had neither any documents to support their association with the defence ministry or the OFB, nor was there any documents of the car. They have been arrested and the car seized, " Superintendent of Police Kunal Aggarwal said.
Identified as Salim Akhtar, Sheikh Asrafuddin, Shakil Ahmed, Sheikh Irfan, Sheikh Shah Rukh and Sheikh Abu, all the six are residents of Kolkata.
Besides getting in touch with Kolkata Police to get details of any criminal antecedents of the accused, police have also informed the defence ministry about the incident.
According to a defence ministry official, the car was hired by the OFB for 'routine purposes' but the contract ended in November 2015 and was not renewed.
Police were also investigating if the accused have any terror link.
An accidental blast at a house in Khagragarh in the district in October 2014 led to the National Investigation Agency (NIA) busting a terror module of Bangladeshi militant outfit Jamaat - ul - Mujahideen Bangladesh.