According to police, the car of Bhaskaran, now working at the regional office of the bank at Kalpetta, was parked in front of his house when the incident happened.
Bhaskaran and his family rushed out of the house and put out the fire, police said.
A poster purported to have been written by Maoists demanding writing off loans taken by farmers was found from the site of the incident, police said.
"It is not the work of any Maoist group. It is by some miscreants. However, we are looking into all possibilities," police said.
The bank had recently initiated action against a farmer who failed to repay agricultural loan taken when Bhaskaran was the manager.
A report from Udhagamandalam in neighbouring Tamil Nadu said security had been tightened on the state's border in Nilgiris district in view of the burning of the car.
Vehicle checking has been intensified since early today and addititional police force deployed to monitor the movement of strangers in the area.
Special Task Force, Police and Forest department officials were carrying out combing operations in the forest areas as a precautionary measure, police said.
