An investigation that was launched last fall into allegations that petroleum giant Exxon Mobil misled shareholders regarding what it knew about global warming has recently gained a large number of new backers. Attorneys general from 15 states, the District of Columbia and the Virgin Islands have announced their support for the investigation, originally launched by New York Attorney General Eric Schneiderman in November of 2015. Schneiderman is using New York state’s Martin Act to investigate potential fraud that the company’s campaign of climate change denial may have perpetrated.

If there are companies, whether they’re utilities, whether they’re fossil fuel companies, committing fraud in an effort to maximize their short-term profits at the expense of the people we represent, we want to find out about it. We want to expose it and want to pursue them to the fullest extent of the law,” Schneiderman said at a news conference, where the participation of the additional states was announced.

The initial investigation was launched following the discovery that Exxon had conducted extensive research into climate change during the late 1970s and into the late 1980s, coming to the conclusion that the use of their product could drastically alter the Earth’s climate. Investigative journalists from InsideClimate News broke the story in September 2015, drawing on extensive interviews with former Exxon employees, scientists and government officials, along with hundreds of pages of internal documents from Exxon itself.

If Exxon Mobil has tried to cloud their judgment, we are determined to hold the company accountable,” explained Virgin Islands Attorney General Claude Earl Walker, referring to the potentially-misled investors.