• A doctor recently claimed on social media that UnitedHealth called her mid-surgery, denied her patient an overnight stay, and threatened legal action for her online posts about the incident after the company retained the defamation law firm Clare Locke.

Two months after UnitedHealthcare chief executive Brian Thompson was killed, UnitedHealth Group has hired a defamation law firm to take on social media posts that it claims are untrue and reckless, according to Bloomberg Law.

The Virginia-based firm Clare Locke claims on its website to be “dedicated to litigating complex defamation matters and representing clients facing high-profile reputational attacks.”

On Jan. 7, a plastic surgeon named Elisabeth Potter posted a video of herself on Instagram claiming that UnitedHealthcare called her mid-surgery and asked her to justify an in-patient stay for a woman who has breast cancer and needed a surgical procedure to treat it. Potter then claimed that the insurer denied the patient an overnight stay and threatened her with legal action for her posts.

She included what appeared to be screen grabs of the letter from Clare Locke, dated Jan. 13. “We are writing to demand you correct your knowingly false, misleading, and defamatory posts regarding UnitedHealthcare,” it reads. The lawyers claim she made an error and that is why the insurer reached out, and that it would never have asked or expected her to step out mid-surgery. Clare Locke asked that she post a public apology and retract her accusations.

“I am a woman taking care of women affected by breast cancer,” Potter wrote on X. “I do this work with all of my heart, and I will continue to speak up for my patients—because they deserve better.”

“There are no insurance-related circumstances that would ever require a physician to step out of surgery, as doing so would create potential safety risks and we would never ask or expect a physician to interrupt patient care to return a call,” a UnitedHealthcare spokesperson told Fortune. “These allegations by a plastic surgeon that UnitedHealthcare denied coverage for the care that a breast cancer patient received are false and UnitedHealthcare had previously approved coverage for the care, including an overnight stay.”

Potter isn’t the only one taking to social media to vent about United Healthcare. Since Thompson was murdered, people glorified his alleged killer and criticized the insurer online for denying claims.

Bloomberg recently reported UnitedHealth contacted the Securities and Exchange Commission about a since-deleted post by billionaire Bill Ackman. “I would not be surprised to find that the company’s profitability is massively overstated due to its denial of medically necessary procedures and patient care,” Ackman had claimed. UnitedHealth shares fell by 4.3% the next day.

Clare Locke was founded by Tom Clare and Libby Locke, who are husband and wife. It co-represented Dominion Voting Systems against Fox News. Dominion sued Fox for $1.6 billion, accusing the outlet of damaging its reputation after Fox wrongly blamed it for switching votes from Donald Trump to Joe Biden in the 2020 election. The case resulted in Fox paying Dominion a $787.5 million settlement.

Clare Locke did not immediately respond to Fortune’s request for comment.