Alaska's attorney general is investigating state emails used by a former aide of Sarah Palin who wrote a book critical of the ex-governor and former vice presidential candidate.

The investigation is focusing on whether Frank Bailey wrongfully used the messages as the basis for the book.

The probe was initiated following an ethics complaint lodged by Anchorage resident Andree McLeod last September.

Assistant Attorney General Margaret Paton Walsh told McLeod on Friday that the state has been trying to determine if it is missing emails and which messages might be in Bailey's possession.

Bailey did not respond to the Anchorage Daily News on Monday. But he told The Associated Press in September that his procedures in preparing his book were lawful.

Bailey's book is due to be released May 24.