Thiruvananthapuram,   In a suspected case of revenge killing, a 43-year-old activist of the Social Democratic Party of India (SDPI) was brutally murdered by a group of men alleged to be RSS activists at Ellapully in Palakkad district on Friday afternoon.

Subair and his aged father Basheer were returning on a bike after attending Friday prayers at a mosque when a car hit the bike and both of them fell down.

Basheer said that four men came in two cars and hacked his son to death, after which they escaped in one car, leaving the other at the place where the crime took place.

"I think I can recognise two of them," said Basheer, who suffered minor injuries after falling down from the bike.

The local SDPI activists alleged that it was a planned attack by RSS/BJP combine.

The police have launched a probe by sending teams to Tamil Nadu, where the killers are believed to have escaped.

Following the gruesome murder, DGP Anil Kant has issued an advisory to all the 14 district police chiefs, urging them to ensure that the force is on high alert.

Doubts are being raised as to whether it was a revenge killing, as in the same area (Ellapully) where this murder took place, a 26-year-old RSS worker, Sanjith, was brutally murdered in November last year, allegedly by SDPI activists.