According to police, the incident occurred at 10 pm. The deceased has been identified as Sub-Inspector Wilson. He was on-duty near the check post when a man opened fire.
"The accused are suspected to be one Abdul Sameem and one Thoufiq," the police stated.
The CCTV footage showed that the duo escaped after the incident.
The police seized three empty shells and two live rounds from the scene of the crime. A massive manhunt has been launched by both the Tamil Nadu and Kerala Police to nab the culprits.
Tamil Nadu Chief Minister K Palaniswami on Thursday assured strong action in the State Assembly to bring to book those who shot to death a police special sub-inspector, when he was on duty at a checkpoint bordering Kerala.
As many as four teams have been set up to probe his killing and the Director General of Police J K Tripathi has been rushed to the spot, he said.
Palaniswami said two unidentified men shot at the SSI, Wilson using a pistol and stabbed him when he was on duty at the Kaliyakavilai checkpoint in Kanyakumari district on the border with Kerala by 9.30 pm on Wednesday.
"Wilson sustained injuries and fell down," the Chief Minister said adding he was rushed to the Kuzhithurai Government Hospital which declared him brought dead.
Two live and two empty bullets were recovered.
Four special teams are investigating the matter while the DGP has rushed to the spot and holding enquiry on the CM's direction.
"The special teams are studying the CCTV footage from that area's shops and houses. The case is under investigation.
The government will take stern action to arrest the offenders soon and get them stringent punishment," he said.
Wilson is survived by wife and two daughters, he said and extended his condolences to his family.
Also, Palaniswami said government job will be provided to one of the family members of the deceased sub-inspector on compassionate grounds besides solatium.