An advocacy group mailed three voter registration letters to Georgia Secretary of State Brad Raffensperger’s dead son, who died two years ago.

Brenton Jay Raffensperger death: What happened to Brad Raffensperger son?

He issued further warnings to groups that have’repeatedly and aggressively’ attempted to register ineligible or deceased voters for the January 5 Senate runoff elections.

Raffensperger said the postcards were all sent by New Georgia Project, a nonprofit that claims to derive its voter information from the state’s official voter lists.

‘This is something that was delivered to our home yesterday.’ We received three of these from the same source. ‘It’s in memory of my son Brenton J. Raffensperger, who died two years ago,’ Raffensperger said at a press conference on Wednesday. ‘He isn’t on our voter registration lists in Georgia.’ We double-checked.’

Raffensperger revealed earlier on Wednesday that his office has initiated an investigation into various organizations, including America Votes, Vote Forward, and the New Georgia Project.

In recent weeks, Raffensperger has released statements warning against efforts to register people who are ineligible to vote in the Senate runoffs or to encourage people to come to Georgia simply to vote.