“The opioid epidemic is a public health crisis,” Healey said. “I am working with my colleagues in actively investigating whether manufacturers used illegal practices in the marketing and sale of opioids and worsened this deadly crisis.”

The coalition is probably examining what exactly the drug makers knew about the addictive effects of the medications, and when they knew it, according to Jon Barooshian, a former state prosecutor in Massachusetts who isn’t involved in the probe. The group is also likely probing what efforts the companies made, if any, to ramp up use of the drugs, such as by encouraging doctors to prescribe them for the widest possible array of pain, as well as in cases when less-addictive drugs would have sufficed.

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"If you market that product for too many types of uses then you boost profits, but you’re also increasing the risk of addiction," said Barooshian, now a white-collar defense lawyer at Bowditch & Dewey in Boston.

The most "sinister" potential wrongdoing would involve companies being fully aware of the addictive nature of the drugs and banking on it to increase profit -- a worst-case scenario similar to what happened with the tobacco industry, Barooshian said.

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Whatever the attorneys general find, they’ll have a wide range of options available, including civil lawsuits and fines levied through settlements that would cover the cost of the handling the epidemic. In some scenarios, criminal cases and punitive damages may be warranted, though that’s less likely, he said.

More than 20 U.S. states, counties and cities have sued firms including Johnson & Johnson, Purdue Pharma Inc., and McKesson Corp. in the past year, claiming they fueled a public-health crisis with misleading marketing and aggressive distribution of opioids. Attorneys general in Alaska and Tennessee are also considering lawsuits as their health and legal budgets are stretched to a breaking point by the surge in addictions, overdoses and crime.

“The opioid epidemic continues to have a devastating impact in Connecticut,” the state’s attorney general, George Jepsen, said Thursday in a separate statement. “It would be irresponsible to predict at this stage whether our efforts will lead to legal action or relief, but Connecticut residents can be assured that we will pursue this investigation fully.”

Drugmakers and distributors defend the safety of prescription opioids and say they work actively to keep the powerful painkillers from being abused.

The Food and Drug Administration has increased its scrutiny of opioids, directing drugmaker Endo International Plc last week to pull its Opana ER opioid from shelves. Endo said it’s working with the agency to address the request.

“Prosecutors across the country recognize that opioid abuse is a critical issue affecting families everywhere,” Eric Soufer, a spokesman for New York Attorney General Eric Schneiderman, said in an email. “This effort reflects the commitment of a bipartisan group of attorneys general to bring their combined resources to bear to take a hard look at every facet of this crisis.”

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