The state of Maryland is uncomfortable with Insys Therapeutics Inc.’s proposed sale of the opioid drug Subsys, raising concerns the buyer would fuel further illegal sales of the drug.

In an objection filed in the U.S. Bankruptcy Court in Wilmington, Del., where Insys is selling off its assets, Maryland authorities said they believe the proposed buyer is linked to a company that has its roots in a mail-order pharmacy that they said “knowingly aided” off-label sales of Subsys, a powerful fentanyl painkiller. The state said Subsys shouldn’t be sold unless safeguards are in place to prevent the buyer from following Insys in feeding drug addiction.

Subsys helped turn Insys into a profit-center in the opioid industry but later spurred civil and criminal investigations of the company, resulting in convictions and guilty pleas for several top executives and Insys itself based on its improper sales tactics.

The drug was approved for patients with breakthrough cancer pain, but Insys engineered sales for off-label use that got around insurance company restrictions and worsened the national opioid epidemic.

Insys filed for bankruptcy in June and said last week it reached a deal to sell Subsys to Wyoming-based BTcP Pharma LLC. Maryland’s lawyers tracked the back story on BTcP Pharma and found what they said were “sufficient red flags” that the deal carries dangers.