On Friday, leftist journalist Kurt Eichenwald, who is epileptic, tweeted that the FBI had arrested the man who had tweeted a strobe-light .gif at Eichenwald, prompting him to have a seizure.

The FBI confirmed to Heat Street that an arrest has been made.

The incident in question occurred in December, when someone calling themselves @jew_goldstein, who was later suspended by Twitter, replied to one of Eichenwald’s tweets with a .gif of a strobe light. According to Heat Street, “The .gif said something along the lines of ‘You deserve a seizure for that post.’”

Eichenwald’s wife replied to his tormentor on Twitter:

Eichenwald, a vehement opponent of Donald Trump, had reportedly been targeted with strobe-light tweets before.

As CBS News reported in 2008, hackers “bombarded the Epilepsy Foundation’s Web site with hundreds of pictures and links to pages with rapidly flashing images. The breach triggered severe migraines and near-seizure reactions in some site visitors who viewed the images. People with photosensitive epilepsy can get seizures when they’re exposed to flickering images, a response also caused by some video games and cartoons.”