PHOENIX (AP) — Lawsuits have been filed challenging the qualifying signatures of two of three Democrats running in the special primary election to replace former U.S. Rep. Trent Franks.

The suits filed Thursday allege enough signatures filed by Brianna Westbrook and Gene Scharer are invalid to bar them from the ballot.

The other Democrat is Dr. Hiral Tipirneni. The lawsuit was filed by a Democratic plaintiff named Lynda Vescio.

No signatures were filed by Thursday's deadline questioning any of the 12 Republican candidates' signatures. A thirteenth GOP candidate withdrew.

Ballots have already been mailed to overseas military voters, making a successful challenge problematic.

The special primary election is set for Feb. 27, with each party's top vote-getter advancing to the April 24 general election.

Franks resigned amid sexual harassment allegations last month.

— This story has been corrected to show the first name of the plaintiff is Lynda, not Lydia.