Whale Oil blogger Cameron Slater believes death threats he is receiving have come from people on the West Coast.
His blog site remains offline after a cyber attack on Tuesday.
An article on the site published on Saturday, on a Runanga man killed in a car crash on Friday night carried the headline "Feral dies in Greymouth, did world a "favour".
The Greymouth Star reported the comments on Monday.
Slater says between 200 and 300 people have since attacked him on Facebook, and he believes he knows where they come from.
He told Radio New Zealand's Morning Report they are vigilantes and said he will take a complaint to the police on Wednesday.
