President Donald J. Trump and other top Republicans were stoking claims that the election had been stolen, and their supporters were protesting in the streets. Members of the far-right group the Proud Boys and people close to Roger J. Stone Jr., including Representative Matt Gaetz, took part in the action as the crowd was chanting “Stop the Steal.”
The time was 2018, the setting was southern Florida, and the election in question was for governor and a hotly contested race that would help determine who controlled the United States Senate.
Now, four years later, the Justice Department is examining whether the tactics used then served as a model for the attack on the Capitol on Jan. 6, 2021.
In recent months, prosecutors overseeing the seditious conspiracy case of five members of the Proud Boys have expanded their investigation to examine the role that Jacob Engels — a Florida Proud Boy who accompanied Mr. Stone to Washington for Jan. 6 — played in the 2018 protests, according to a person briefed on the matter.
The prosecutors want to know whether Mr. Engels received any payments or drew up any plans for the Florida demonstration, and whether he has ties to other people connected to the Proud Boys’ activities in the run-up to the storming of the Capitol.
Different prosecutors connected to the Jan. 6 investigation have also been asking questions about efforts by Mr. Stone — a longtime adviser to Mr. Trump — to stave off a recount in the 2018 Senate race in Florida, according to other people familiar with the matter.
Mr. Gaetz, Republican of Florida, participated in the 2018 demonstration, but the extent and nature of his involvement remain unclear.
Fritz Scheller, a lawyer for Joel Greenberg, a local Florida tax collector who is cooperating with the government in an investigation into Mr. Gaetz, declined in response to questions to discuss the specifics of what his client told the authorities about the 2018 incident. Still, Mr. Scheller said, “A significant aspect of Mr. Greenberg’s cooperation has been his assistance in matters involving efforts to subvert the democratic process.”