OxyContin

Purdue Pharma, the maker of Oxycontin, conducted what may be the most extensive investigation yet of the Sackler family, exploring whether they committed crimes or financial improprieties, but the company has kept most of its findings secret.

Critics say the settlement doesn't hold company executives or members of the Sackler family accountable for their aggressive marketing of OxyContin, which helped fuel the nation's opioid epidemic.

The revelation comes after almost two dozen states reached a tentative settlement with the maker of OxyContin.

Government officials are bickering over hundreds of millions of dollars in settlements paid by Big Pharma, stemming from the nation's deadly opioid epidemic. The pharmaceutical industry paid out more than half a billion dollars over the last year alone. All sides expect the scale of settlements to grow fast as more cases go to trial.

The Massachusetts attorney general alleges that the family behind Purdue Pharma knew that OxyContin was causing overdoses, yet continued to cash in. New documents in the case were released Thursday.

The report released by Missouri Democratic Sen. Claire McCaskill says the cozy relationship between pain advocacy groups and pharmaceutical companies may have played a key role in the opioid crisis.