The U.S. Justice Department is continuing its probe into whether the nation’s three largest movie theater chains — AMC Entertainment, Regal and Cinemark — have used their market power to prevent independent theaters from securing potential blockbuster releases.

AMC received a Civil Investigative Demand from the Justice Department’s Antitrust Division on Thursday and one from the Ohio Attorney General on Friday requesting “the production of documents and answers to interrogatories concerning potentially anticompetitive conduct, including film clearances and participation in certain joint ventures,” AMC said in a Securities and Exchange Commission filing.

“We do not believe the company has violated federal or state antitrust laws and are cooperating with the relevant governmental authorities,” the exhibition giant said in its filing on Monday. “However, we cannot predict the ultimate scope, duration or outcome of these investigations.”

A Spanish-language Houston moviehouse sued AMC Theaters last month for using its market power to block it from getting studio licenses to screen films like “World War Z,” “Iron Man 3” and “Fast & Furious 6.”

Viva Cinema Theaters said it went out of business six months after opening because AMC threatened distributors that it would not show any of their first-run movies, English or Spanish, at any of its 30-screen theaters in Houston if they licensed to Viva. The suit claimed violations of the Sherman Antitrust Act, tortious interference and violations of a Texas antitrust law.