Eli Lilly has been served a subpoena from the Office of the Attorney General in New York because of the pricing and sales of its insulin products. This report was confirmed by the drugmaker in a filing they have sent to the Securities and Exchange Commission.

Similarly, Offices of the Attorney General in Nevada, Hawaii, California, Florida, Mississippi, and Washington DC also requested to be informed on the details of their pricing. New Mexico and Washington also issued civil investigative demands to Eli Lilly.

Eli Lilly, however, did not respond to requests for comment.

Eli Lilly is the creator of the bestseller diabetes treatment Humalog. Aside from them, other manufacturers have been scrutinized by the Congress and the White House over the high prices of insulin, which has been used in diabetes treatment for over 100 years.

According to the Centers for Disease Control and Prevention, more than 30 million Americans suffer from diabetes. The cost of buying insulin every year has doubled from $2,900 in 2012 to $5,700 in 2016, according to the Health Care Cost Institute. The drugmaker Eli Lilly makes $3 billion in annual sales.

The members of Congress started investigating this matter earlier in the year because of the fast-rising cost of insulin, asking manufacturers to explain why the prices have to increase.

The drug producers pointed their fingers to pharmacy benefit managers or the middlemen, as they are responsible for the prices seen by the customers. They should discuss the rebates earned by these middlemen who negotiate sales.

Moreover, Eli Lilly mentioned that their product prices have actually decreased once the rebates and discounts are factored in.

In a preemptive action, Eli Lilly has launched a product called Insulin Lispro. It costs 50 percent lower compared to Humalog, at $137.35 per vial.