The New York Post cited "several" unnamed sources who claim the DoJ is reaching out to "a handful of the country's biggest media and technology companies" to get their opinions on Apple, which is rapidly becoming the dominant force in several areas of new media.
"The [Justice Dept.] is doing outreach," one Hollywood industry source told the paper. "You can't dictate terms to the industry. The Adobe thing is just inviting the wrath of everybody."
"If Apple thinks it's going to increase its monopoly with the iPad, it should look at the history of other walled gardens," added another.
The expanded probe will reportedly see the DoJ ask questions about the terms Apple sets forth to developers who want to write applications for the iPad and the company's other iPhone OS devices.
The inquiry began earlier this month after investigators became interested in allegations that Apple used its market power in an effort to prevent music labels from participating in exclusive music distribution deals with rival Amazon.
Apple is also among the tech companies being investigated by the DoJ over hiring practices that allegedly conspired to prevent competitors from hiring each other's employees. That investigation also involves Google, IBM and Intel.