Less than two weeks after whistleblower Frances Haugen testified in Congress that Facebook has repeatedly lied to the public about the ways its platform causes harm to society, another whistleblower is going to share her account with British lawmakers.

Former Facebook data scientist Sophie Zhang will testify before the British Parliament on Monday, potentially adding fuel to a global firestorm that lawmakers and critics have referred to as Facebook’s “Big Tobacco moment.”

Damian Collins, chair of Parliament’s Online Safety Bill committee, said Zhang, who will appear via video link, will be questioned about “her work as a data scientist for the Facebook Site Integrity fake engagement team, dealing with bot accounts, often operated by government-backed agencies in countries such as Russia.”

He continued: “These networks have sought to spread disinformation and interfere in the politics of other countries. Combating inauthentic accounts spreading disinformation is an important challenge in making social media safer and we want to understand what the companies are doing now, and what more should be done.”

Haugen testifiedthat Facebook knew its platform hurt the self-image of teen girls, and that executives also resisted making changes to the company’s software that would have protected its users from harms such as hate speech, because doing so would hurt the company’s growth.

Haugen will also give evidence to the Parliament committee on Oct. 25.

While Facebook has endured many controversies, including Russian disinformation on its platform and the Cambridge Analytica privacy scandal, the documents brought forth by Haugen give a much more complete and potentially damaging picture of the company’s intentions.

When Zhang quit the company in 2020, she left with documents alleging that it had ignored her findings for nearly a year that Honduras’s president was running a disinformation campaign on Facebook to manipulate his popularity, and that it also had been slow to take action on a state-backed harassment campaign against journalists in Azerbaijan. Zhang first shared her story in the Guardian late last year.

Facebook has said the allegations by Haugen and Zhang, who both worked under a division called civic integrity, are mischaracterizations of the company’s work to protect the public. The company has said Haugen did not work directly on the issues she testified about. In Zhang’s case, it said it ultimately took action on the abuse she uncovered and that the time lag in enforcement was not an attempt to protect powerful people who use its service.

Zhang confirmed that she recently provided documents to law enforcement but declined to comment further, saying it was not appropriate to comment on ongoing investigations.