Sanders, who is running for state Senate, says their claims are baseless and have no merit.
The mailer features Rep. Tim Griffin's endorsement of Sanders. Griffin, a Republican is running for re-election to the House for the seat representing District 2.
Candace Martin, spokeswoman for the Democratic Party of Arkansas, says the party is considering filing a complaint with FEC. She questioned if Sanders got money or an in-kind donation exceeding the donation limit to pay for the mailer.
From the the Democratic Party of Arkansas, in an email to KARK:
"This is what we believe has been violated with FEC code for backup:
a) The need to register a committee if the mailing costs more than $1,000 2 USC 441i(f).
b)The potential that it is an excessive in-kind contribution if the share of the mailing attributable to the federal candidate exceeds $2,500,
c) The failure to provide proper FEC disclaimer in a box 2 USC 441d"
Sanders said his campaign alone paid for the mailer.