A key House Republican on Tuesday defended his move to subpoena two Democratic attorneys general over their aggressive efforts to investigate energy companies, and accused them of refusing to comply in order to hide the details of their efforts from Congress.

“Your office, at the behest of various environmental groups, is investigating alleged fraud by Exxon and others, and to that end has issued subpoenas, demanding the production of documents and communications between, among others, Exxon and scientists, both internal and external, who conducted research relevant to the issue of climate change,” House Committee on Science, Space, and Technology Chairman Lamar Smith, R-Texas, wrote to the AGs from New York and Massachusetts.