An Oklahoma City man is facing federal charges after investigators linked him to a nationwide campaign involving hundreds of threatening letters sent to public officials and other prominent recipients before two election cycles. Robin Martin was arrested Monday and charged with conveying a hoax and mailing threatening communications.

According to an FBI affidavit made public Tuesday, investigators believe more than 700 mailings were associated with the same sender. The envelopes contained white powder that, in cases where testing has been completed, was identified as yeast or flour. Authorities cautioned that not all the letters have been fully tested, and the investigation remains ongoing.

The mailings targeted a broad range of recipients, including election officials, members of Congress, political pollsters, news organizations and federal law enforcement agencies. The FBI said the investigation began in 2024, when election officials across the country reported receiving letters containing a white substance and a three-page message declaring war. Some of the correspondence also included messages written in ultraviolet-reactive ink that could not be easily seen under ordinary lighting.

The sender used the return address "U.S.T.E.A.," an apparent reference to the "United States Traitor Elimination Army," and listed Takoma Park, Maryland. A recurring warning threatened recipients with impending arrests for treason "or worse!!" The FBI said the letters also included claims about the 2020 election and warnings about alleged problems surrounding subsequent elections.

The mailings prompted significant security responses. In October, election offices in Louisiana and Oklahoma were evacuated after receiving suspicious packages. Election authorities in numerous other states, including Idaho and Florida, reported receiving similar correspondence or having letters intercepted by the U.S. Postal Service. Federal authorities had previously warned congressional and election offices to treat suspicious mailings as potentially hazardous while the FBI and Postal Inspection Service investigated.

Investigators say they developed evidence connecting Martin to the mailings through surveillance footage and forensic examination. FBI agent David Cole said video showed Martin's vehicle stopping at mailboxes at Postal Service facilities in Oklahoma City, Dallas and San Antonio during October. Investigators also recovered fingerprints from a letter addressed to FBI Director Kash Patel, whose first name was written as "Kashyap."

The FBI further said it believes Martin used the name George Livingston when posting a message to a Democratic Socialists of America email list in October. The message reportedly accused members of being traitors and warned they could be arrested for treason if they voted in the November 3 election. The organization apparently cooperated with investigators.

Martin was expected to make his initial appearance Tuesday in U.S. District Court in Oklahoma City. Court records did not identify an attorney representing him, and relatives contacted by reporters did not immediately respond to requests for comment.

The case has raised concerns about threats directed at election administrators and public officials during a nationwide election period. Although the white powders tested so far were identified as ordinary substances, the volume of correspondence, threatening language, and broad range of recipients triggered evacuations and a federal investigation. Martin has been charged, and the allegations have not yet been tested in court.