The couple-Rajan, 47, and his wife Ambili, 40, natives of Nellimoodu at nearby Neyyattinkara- succumbed to burns at the government medical college hospital in Thiruvananthapuram after they sustained multiple organ failure on Monday.
Security was tightened in Tamil Nadu on Friday following reports that six members of the terror outfit LeT had infiltrated the state by sea.
The reports suggested six members of the terror outfit infiltrated into the state by sea from Sri Lanka and moved to different cities, including Coimbatore, according to the police.
The director general of police said everyone in the force should have to perform their duties irrespective of their religion and politics.
Prohibitory orders were imposed in Delhi and parts of Karnataka. Police kept tight vigil in Kerala. In Gujarat, 50 people were arrested for Thursday's violence.
He was arrested based on evidence police gathered during the process of investigation into the case.