Thornton Township Supervisor Tiffany Henyard filed a lawsuit Thursday seeking to overturn the results of what she believes was an improperly run Democratic caucus that kept her off the ballot.

Henyard, who has drawn criticism for lack of transparency and excessive spending both as supervisor and Dolton mayor, was unable to compete for the nomination for supervisor because she did not comply with rules set by the Democratic Party ahead of time, according to the lawsuit.

She is suing the Thornton Township Democrats as well as committeeman and state Sen. Napoleon Harris, who received the Democratic nomination for supervisor, for denying voters their full rights to choose their own candidates. During a Thursday news conference, recorded on YouTube, Henyard said hundreds of her supporters were unable to enter the building and vote for her.

“That evening, I was very confident that I would be victorious and given the nomination because the people really do stand with me,” Henyard said. “But I was not able to display that because our voices were taken.”

Dixmoor Mayor Fitzgerald Roberts was also named as a plaintiff in the lawsuit, though he released a statement Thursday stating his inclusion was a mistake on the part of Henyard’s attorney, Max Solomon. Solomon confirmed Friday he would refile the suit without Roberts’ name.

The lawsuit alleges the township Democrats and Harris acted improperly by allowing members who met at the Homewood-Flossmoor Park District auditorium for a private event to stay there for the following caucus, while denying entry to others.

“Our contention is that people who were already inside for the quote unquote party event were left remaining inside party event, and only a few more that were hand picked,” Solomon said Friday.

Solomon said by allowing attendees to stay in place rather than requiring them to reenter, the committee could not have properly checked that those voting met the qualifications codified in state statute, including being township residents.

Henyard also alleges the party and Harris as committeeman failed to provide the rules of the caucus to participants with due notice. The rules required people nominating candidates be party members in good standing and that they nominate an entire slate of candidates to all positions up for election.

Henyard attempted to nominate herself for supervisor on the auditorium floor but failed to meet requirements that there be an entire qualified slate of candidates filed in writing by Dec. 2.

The lawsuit alleges Harris set those rules himself Nov. 26, and that they were to be approved by qualified voters at the caucus as required by state law, but the rules “were never provided to caucus participants, either in advance of the caucus, or at the caucus, or during caucus.”

The caucus rules deliberately favored Harris and were “deliberately and arbitrarily designed to eliminate any chances of Plaintiff, Tiffany Henyard,” the lawsuit states.

Attorney Burt Odelson, who is representing Harris and the Thornton Township Democrats, said Friday Henyard’s claims are frivolous and should be immediately dismissed in court.

“This is garbage — it’s incompetent,” Odelson said. “It has no relation to the law at all, and it should never have been filed.”

He said the Democratic Party is a “private club” able to set its own rules for participation and that Solomon will have to answer for his mistaken addition of Roberts’ name to the suit.

“It’s so bad that it could get a couple of them in trouble,” Odelson said.

Roberts said in a statement his naming in the lawsuit resulted from “vastly different” interpretations of a conversation he had with Henyard following the caucus.

“I have not authorized or initiated any legal actions, nor was I consulted about any such filings,” Roberts said. “I appreciate the work Supervisor Henyard and Sen. Harris have done for Dixmoor. My focus is on the Village of Dixmoor and helping the residents here. I have no desire to be a part of this lawsuit.”

The lawsuit asks the court to require the party hold a new caucus conducted and overseen by public members.

ostevens@chicagotribune.com