In the second such fatal attack on its leaders, a local functionary of Hindu Munnani was on Monday found murdered in Rameswaram, Tamil Nadu, police said.
55-year old Nambu alias Kuttainambu, the secretary of Hindu Munnani's Rameswaram unit, was found dead with injuries in the head and chest caused by a boulder, they said.
The murder, coming close on the heels of the killing of Hindu Munnani state secretary Vellaiyan by a gang in Vellore last week, sparked tension amid suspicion that leaders of the religious and cultural organisation, founded in 1982, were being targeted.
Officials said they were investigating the case in all angles.
Meanwhile, police arrested one Ramachandran who allegedly confessed he murdered Nambu due to previous enmity.
Police claimed Ramachandran said his family and Nambu were at loggerheads for a long time and he along with some others murdered him.
Police personnel had been posted in the sensitive areas in the holy island which has a sizeable population of Muslims, they said.
Meanwhile, BJP local leader Muralidharan appealed to chief minister Jayalalithaa to provide assistance to the family of Nambu, who left behind six daugthers and a son.