The family that owns controversial opioid manufacturer Purdue Pharma has transferred more than $10bn (£7.6bn) from the company to its personal trusts and holdings in the last decade.
An audit carried out by consultants Alix Partners found that the billionaire Sackler family were given $10.7bn in payouts by the firm, which makes Oxycontin.
The findings, which were first disclosed by the New York Times, will add to the pressure on the family to pay to resolve lawsuits faced by Purdue as a result of the ongoing opioid crisis.
Legal action from state and local governments claim that the company has played a part in enhancing the health emergency, which has seen almost 400,000 people die since 1999.
The lawsuits differ in nature, but many have claimed that Purdue misled both doctors and patients over the risk of both addiction and overdose, claims that the company denies.
They also say that Purdue marketed oxycontin aggressively.
New York Attorney General Letitia James said in an statement: “We need full transparency into their total assets and must know whether they sheltered them in an effort to protect against creditors and victims.
“We are committed to holding the Sacklers responsible for the role they played in fueling the opioid crisis and will not stop fighting until we have achieved justice for victims.”
In September Purdue filed for bankruptcy protection in order to halt thousands of lawsuits.
The firm is trying to generate support for a settlement which could be up to $10bn.