The CCTV footage showed them armed with weapons. The footage also showed the killers fleeing the scene after shooting the cop.

A high alert has been sounded in the border areas of the state following the incident and an intense hunt has been launched in Kanniyakumari, Tirunelveli and Tenkasi districts to nab the assailants.

Wilson, the 56-year-old deceased officer, intercepted a Scorpio SUV, which entered Kanyakumari district around 10 pm. The occupants of the car opened three rounds of fire at the police officer, inflicting bullet injuries on his forehead, abdomen and a leg.

Wilson had earlier worked with the Special Task Force (STF).

Tamil Nadu police chief is in Kerala in connection with the investigation. The links of the killers to Islamist and Naxalist outfits are also being investigated.