Apple failed to meet First Amendment requirements in its case against journalists in the US, court documents have revealed.

The Electronic Frontier Foundation (EFF) last week won the right to have previously secret documents filed by the computer company unsealed. They revealed that Apple had issued subpoenas against two reporters' forcing them to disclose anonymous sources without first conducting a thorough investigation inside the company.

The EFF called it a "crucial issue in the case" because under the First Amendment and the California Constitution, Apple was required to have exhausted all other alternatives open to it before trying to subpoena journalists.

Journalists worldwide are watching the case because of its severe implications for investigative work.

The unsealed documents show Apple never took depositions from employees, never issued subpoenas (other than to the journalists), and never asked for "signed declarations or information under oath from its own employees," the EFF said.

The EFF and co-counsels Thomas Moore III and Richard Wiebe, are representing journalists from AppleInsider.com and PowerPage.org. Both sites printed articles about a secret Apple product, codenamed "Asteroid". It was described as a Firewire audio interface for GarageBand.

Apple took legal action claiming violation of trade secret laws. In December, the company sued several unknown parties, known as "John Does", who allegedly leaked information about the product.

A California Superior Court ruled earlier this year that the subpoenas could be issued, both to the journalists' e-mail providers as well as the publishers of the site. The journalists appealed the ruling, so the court ordered Apple to prove why the appeal shouldn't be granted.

No date for the Appeal Court hearing has been set.