A Georgia poll worker has been arrested on US charges that he sent a letter threatening to bomb election workers that he wrote to appear as if it came from a voter in the presidential election battleground state, Reuters reports.

Federal prosecutors said Nicholas Wimbish, 25, had been serving as a poll worker at the Jones County Elections Office in Gray, Georgia, on October 16 when he got into a verbal altercation with a voter.

The next day, Wimbish mailed a letter to the county’s elections superintendent that was drafted to appear as if it came from that same voter, prosecutors said.

Prosecutors said the letter ended with a handwritten note: “PS boom toy in early vote place, cigar burning, be safe.”

Georgia is one of seven closely contested states expected to decide the outcome of today’s presidential election match-up between Republican former President Donald Trump and Democratic Vice President Kamala Harris.