Comedian Patton Oswalt's query — "The FUCK is going on? Is this real?" — was retweeted nearly 3,000 times in less than 24 hours. He was responding to a tweet that framed the letter as Johnson "threatening to report his constituents to the police for requesting a townhall."

A Facebook post from Citizen Action of Wisconsin added fuel to the fire on Wednesday afternoon.

The group clarified that an individual, not the organization, had received the letter, "following a series of efforts to contact his/her elected official."

"We have also heard rumors that many more are also receiving these Cease/Desist letters," the group wrote.

No evidence has been provided to back up that claim, and Johnson's office disputes it. This is one of two such letters the office has sent in two years, a staffer said.

Kevin Kane, organizing director for Citizen Action of Wisconsin, said he has not seen any additional letters, but has heard claims that they exist.