BOSTON (AP) — Democratic Massachusetts Attorney General Maura Healey is asking Exxon Mobil to preserve all alias email accounts of company executives.

Massachusetts and New York are investigating whether Exxon misled investors and the public about the risks climate change posed for the oil and gas company.

Monday's letter comes after it was disclosed former Exxon CEO Rex Tillerson, the current U.S. Secretary of State, used an alias email account.

Healey's office said in the letter: "Alias email addresses of Exxon executives and documents associated with them must be preserved."