INDIANAPOLIS (AP) — Indiana Attorney General Curtis Hill is working with a coalition of his counterparts across the U.S. to investigate whether opioid manufacturers have broken any laws.

The Republican said Thursday that the bipartisan group of attorneys general is particularly interested in exploring if drug companies illegally marketed or sold opioids.

Opiate-fueled drug overdose deaths have surged across the country in recent years. Indiana has had an almost 10 percent increase since 2014.

Hill says the group is not divulging the target of its investigation. But he says they are reviewing what role manufacturers may have played in creating or prolonging the problem.