In an SEC filing, Eli Lilly (NYSE:LLY.N) revealed that it had received a subpoena from the U.S. Department of Justice connected to a manufacturing site in New Jersey that produces bamlanivimab, one of two COVID-19 monoclonal antibodies it produces. The plant also produces the blockbuster Trulicity and cancer drugs.

Lilly did not state which types of documents the federal government had requested but noted that it is cooperating with the criminal probe. The U.S. government has not made any specific accusations against Lilly.

According to a Reuters report, Lilly employees had accused an executive of modifying federal documents to cover up quality control problems at the facility in Branchburg, New Jersey.

FDA officials inspected the plant in November 2019 and reported discovering missing data related to various manufacturing processes. The agency concluded that the facility had two counts of inadequate “control of computer systems.”

The FDA used its “Official Action Indicated” designation to refer to the quality control problems at the Branchburg plant. That designation means the agency will recommend “regulatory and/or administrative actions.” If not resolved, the designation can lead the FDA to block the sale of drugs from the facility.

After the FDA inspection, Lilly noted that it had moved to swiftly resolve the problems. The company also stated that it prioritizes the safety and quality of its products.

The company has also said that none of the issues FDA found related to the quality of its commercialized products.

Lilly said it had hired external counsel to oversee an independent investigation of the Branchburg operations.

Earlier this year, Reuters reported that a Lilly human resources employee claimed she lost her job at the Branchburg factory after launching an internal investigation of employee complaints about manufacturing problems, missing records and staff shortages.

The company has denied any retaliation against employees.