Plaintiffs attorneys in a proposed privacy class action against Google are asking a federal judge to order additional sanctions against the tech giant for allegedly failing to hand over documents revealing that the company tracks and collects user data in private browsing mode, an allegation at the center of the lawsuit’s claims, according to a redacted court filing.

In a supplemental sanctions brief Thursday, attorneys from Boies Schiller Flexner, Susman Godfrey and Morgan & Morgan claim that Google, which is represented by Quinn Emanuel Urquhart & Sullivan, “knowingly hid” that it was logging and using private browsing data for business purposes while participating in more than six-month special master process and discovery disputes, finally disclosing the documents on June 14.