RALEIGH, N.C. (AP) — Internal emails between staff at North Carolina’s environmental agency suggest state regulators were coordinating with Duke Energy before intervening in efforts by citizens groups trying to sue the company over groundwater pollution leeching from its coal ash dumps.

The emails were provided Thursday to The Associated Press by the Southern Environmental Law Center, which had filed notice in January 2013 of its intent to sue the nation’s largest electricity company under the Clean Water Act.