Crystal McKellar, former general counsel of Mithril Capital Management.

Peter Thiel's venture capital fund, Mithril Capital Management, has accused its ex-general counsel, Crystal McKellar, a former child actress known for her role on the "The Wonder Years," of launching a "whisper campaign" to discredit the firm and lure away its investors. 

"Swampy" is how McKellar described Mithril, which Thiel, a billionaire investor and entrepreneur, co-founded with Ajay Royan. She added in an email that the "allegations of wrongdoing are unequivocally false, and it will be a simple matter to prove them false if it gets that far."

Mithril filed a complaint against McKellar on Wednesday in Travis County District Court in Austin, Texas, where the firm is headquartered. 

McKellar portrayed Becky Slater on "The Wonder Years" alongside her sister, Danica McKellar, who starred as Winnie Cooper. Both were love interests of the character Kevin Arnold, played by Fred Savage. Crystal McKellar went on to attend Yale University and Harvard Law School. 

She joined Mithril as the firm's GC in 2012 and was "separated from employment" in February, Mithril states in its petition for injunctive relief. The firm says it gave McKellar a "substantial severance" along with the courtesy title of advisory managing director and an ongoing consulting role. 

Mithril asserts it "severed all ties" with McKellar in July as it became aware of her effort to sully the firm's reputation. McKellar wrote that she "left Mithril earlier this year when it became clear to me that Mithril's leadership was lying to its investors and that the promises it had made were not going to be kept." 

"This is about Mithril's investors, who are families, foundations, and charities that help the most vulnerable Americans, and the pension funds that permit our public servants to retire with dignity," McKellar wrote. "These investors placed their trust and money in promises that were made by Mithril."

After she was removed from the GC role, McKellar signed separation and consulting agreements with confidentiality, noncompete, nondisparagement and nonsolicitation covenants—then "almost immediately … began to materially breach these agreements," according to Mithril. 

The firm, which is seeking more than $1 million in damages, asserts that McKellar launched an anonymous letter-writing campaign to disparage Mithril with false accusations about its business dealings in an attempt to recruit the firm's investors to a competing fund that she was forming called Anathem Ventures based in San Francisco.  

McKellar denies the accusations and says she has "not and will not be accepting any Mithril investors into my fund." She added venture fund investors "are locked in; they cannot simply move a capital commitment from one fund to another."  

Meanwhile, Mithril says it hired a forensic handwriting expert who determined with a "high degree of probability" that McKellar sent a letter to several senior executives at one of Mithril's largest portfolio companies claiming that Royan had "grossly overstated" the firm's success during an interview with Fortune magazine. 

In February, around the same time that McKellar and Mithril began to split, tech news website Recode reported in a story citing anonymous sources that Mithril was a "slow-burning mess" and in "disarray" as it faced questions about its finances. In September, the website reported that the FBI was investigating Mithril for possible misconduct. 

Mithril states in its petition that it "proactively reached out to the government in order to protect Mithril's limited partners, employees and portfolio companies," because it suspected that McKellar was spreading rumors about the firm being under investigation.  

Mark Holscher and Rebekah McEntire of Kirkland & Ellis in Los Angeles and Houston, respectively, represent Mithril. They were not immediately available for comment.