Two members of the Sackler family, which owns OxyContin maker Purdue Pharma, were scheduled to testify Thursday before a House panel investigating the opioid epidemic, according to Reuters.

David Sackler and Kathe Sackler agreed to testify before the House Oversight Committee. They both previously served on Purdue Pharma’s board. Purdue Chief Executive Craig Landau is also scheduled to testify at the hearing.

In a letter to the attorney for David Sackler and Kathe Sackler, Committee Chairwoman Carolyn Maloney wrote, “The Committee has obtained documents showing that members of the Sackler family were closely involved in Purdue’s efforts to grow the market share for OxyContin and other opioids, even after entering into a settlement with the Department of Justice on charges of misbranding — for which Purdue paid $600 million in fines for misleading the public about OxyContin’s risk.”

Last month, Purdue Pharma pleaded guilty to federal criminal charges related to the marketing and distribution of OxyContin. The move formally ended a major investigation that led to a multibillion-dollar settlement between Purdue Pharma and the government.