Josh Hawley, the Republican candidate for Senate in Missouri, on Saturday, demanded an FBI probe of a dirty-tricks campaign mailer that wrongly accuses him of opposing gun rights.
The mailers urge voters to back a Libertarian or Independent voter over Mr. Hawley and do not include required disclaimers identifying who paid for them.
“Voters telling me about fake & illegal mailers pro-Dem group is putting out. There should be an FBI investigation,” Mr. Hawley, the state attorney general, wrote on Twitter.
He called for Democrat incumbent Sen. Claire McCaskill to cooperate in a probe.
“As the beneficiary of this Kavanaugh-style illegal smear campaign, I hope @clairecmc will cooperate with the investigation fully #MoSen,” tweeted Mr. Hawley.
Mrs. McCaskill’s campaign denied involvement in the mailers.
Mrs. McCaskill and Mr. Hawley are locked in a neck-and-neck race that could determine which party controls the Senate after Tuesday’s vote.
Other state Republican leaders have called for a federal investigation of the mailer.
Treasurer Eric Schmitt said the mailers appear designed to help Mrs. McCaskill, who is fighting for a third term in an increasingly red state that backed President Trump by nearly 19 points in 2016.
The ads, which began appearing in mailboxes this week, encourage voters to support the Libertarian or Independent candidates by criticizing Mr. Hawley’s position on gun rights and other issues, according to the Associated Press.
Mr. Hawley has been endorsed by the National Rifle Association.