The Justice Department is looking into whether Apple's iTunes Store violated antitrust law, according to the New York Times. It's at least the fourth federal inquiry into the company in less than a year.

Just a couple of weeks ago came news that the Justice Department was negotiating an antitrust investigation into Apple over its rules for iPhone development, with the Federal Trade Commission also interested in pursuing that case. In the fall, Apple responded to an FCC inquiry over why Apple refused to allow a Google Voice program onto its app store. And Apple has also had to deal with a Justice Department investigation into whether it illegally conspired with other tech companies to stop employee poaching.

The fourth and newest federal inquiry may revolve around reports, first floated in Billboard magazine, that Apple threatened to punish music labels that participated in an online music promotion from rival media retailer Amazon.com, according to the Times. Someone should just explain to the Attorney General that Apple was just offering the labels freedom from messy, headache-inducing competition.