Washington: On Thursday, the Department of Justice filled its response to Apple's latest brief and this time the department adopted a harsher tone than it had previously.

In its latest response, the government threatened to take the entire source code to iOS and the "private electronic signature" which is needed for access to the code. Those two items would allow the government to build its own OS and unlock the Apple iPhone 5c that was used by slain terrorist Syed Farook.

According to the government, the phone could contain useful information, including the name of a possible third shooter which was seen by some witnesses.

Meanwhile, Apple has claimed that building the special version of iOS as requested by the government would be like playing with fire. The Cupertino-based tech giant said that if the code would fell into the wrong hands, the information stored in every iPhone in the world would be vulnerable to hacking.

The Apple versus government fight is set to continue until the case finally reaches the Supreme Court. Whoever loses at the District Court level will definitely appeal the verdict.