Connecticut is investigating Amazon’s activities in the e-book market.

Connecticut’s top law enforcement official said Wednesday that he is conducting an antitrust investigation into how Amazon operates its e-book business.

William Tong, Connecticut’s attorney general, said in a statement that the state “is undergoing an active and ongoing antitrust investigation against Amazon of potentially anticompetitive terms” in the e-book distribution agreements the company has with certain publishers.

The investigation is the latest antitrust investigation into Amazon publicly disclosed. Officials in California and Washington have scrutinized how the company treats independent merchants who use its markets. The Federal Trade Commission also has its own investigation of the company, which critics say has grown into a dominant online retailer by crushing smaller competitors.

An Amazon spokesperson declined to comment. The investigation was previously reported by The Wall Street Journal.

Amazon started selling books in the 1990s. It introduced its Kindle e-reader in 2007. The business quickly attracted the attention of regulators. In 2012, the Justice Department sued Apple, saying it conspired with major publishers to increase the price of e-books beyond the $ 9.99 Amazon charges.

Connecticut is one of the states that has filed a lawsuit against Apple. Mr. Tong, a Democrat, said in his statement that his office “continues to actively monitor this market to protect fair competition for consumers, authors and retail other e-books ”.