Leslie Smith has made good on her promise to challenge the UFC’s labor practices.

The former UFC women’s bantamweight fighter filed a charge Wednesday with the United States National Labor Relations Board (NLRB), MMA Fighting confirmed. The complaint, written by labor attorney and Project Spearhead advisor Lucas Middlebrook and obtained by MMA Fighting, alleges that the UFC’s decision to let Smith go was “based on the animus it held toward her engagement in protected activity.”

Smith is one of the linchpins in the effort to organize and eventually unionize fighters. She is the interim president of Project Spearhead, which is asking UFC fighters to sign authorization cards to determine whether or not they are employees or independent contractors. Smith wholly believes fighters are employees, though the UFC currently classifies them as contractors.

On April 20, Smith said she was essentially bought out of her contract by the UFC. Smith was supposed to fight Aspen Ladd at UFC Atlantic City one day later in the last fight on her contract, but Ladd missed weight by 1.8 pounds. At that point, Smith said she could have contractually gotten paid had she decided not to fight.

Instead, she said she asked the UFC about extending her contract two more fights. Smith said the UFC — through general counsel Hunter Campbell, per the complaint — told her it was not interested in re-signing her. The UFC paid Smith her show money and win bonus, considering that the fulfillment of her contract. The UFC compensating a fighter with his or her show money and win bonus when a fight does not happen is rare, and even more infrequent when a fighter does not compete after an opponent misses weight.

Middlebrook wrote in the complaint that Smith never accepted money “as a quid pro quo for full satisfaction of ZUFFA’s contractual obligations remaining under her existing Promotional Agreement.”

The UFC has yet to comment publicly about this matter. ESPN’s Brett Okamoto reported today that the UFC’s interpretation of these events differs from Smith’s interpretation.

“There simply can be no dispute ZUFFA took adverse action against Ms. Smith, and based on the facts set forth herein and those to be uncovered in the investigation into this issue, ZUFFA’s animus toward Ms. Smith’s protected activity was the substantial or motivating reason for the adverse action(s) taken against her,” Middlebrook wrote in the charge to the NLRB.

Also noted in the charge was that Smith had won three of her last four fights and was ranked No. 9 in the UFC’s official rankings. That one loss during that timespan was against Cris Cyborg, who Middlebrook noted, “is considered to be the best female mixed martial artist in the world.”

On April 23, Smith said on The MMA Hour that she was considering legal action against the UFC. That day, she started a gofundme campaign to help pay for her lawyer fees.

The complaint reads that, by letting Smith go, the UFC “has further cultivated a climate of fear currently existent within its fighter employees as it relates to engagement in protected activity under the [National Labor Relations Act].”

“Leslie Smith was one of the only UFC fighters willing to openly exercise her rights to form, join or assist a union,” Middlebrook wrote in the complaint. “ZUFFA, with the termination of Ms. Smith, has delivered an unlawful message to the remainder of its fighter employees, which is: dare to form, join or assist a union and you too will accompany Ms. Smith not fighting in the UFC. This message contravenes the very purpose of the NLRA and ZUFFA cannot be allowed to continue flouting the Act. No person or entity is above the law.”