Last month, a federal judge asked Apple to help the FBI unlock an iPhone belonging to Syed Farook, who was responsible for the shootings in San Bernardino in December which left 14 people dead.
The judge asked Apple to provide "reasonable technical assistance" to the U.S. authorities, which would require the technology giant to overhaul the system that disables the phone after 10 unsuccessful password attempts. Once this feature kicks in, all the data on the phone is inaccessible. Apple declined to help the FBI.
At the time, Apple chief executive Tim Cook called the order "chilling" and said that it would require writing new software that would be "a master key, capable of opening hundreds of millions of locks". Cook's argument was that if the FBI could access this iPhone, nothing would stop them from doing it to many others.
Law enforcement authorities insisted that it was a one-off request. As a result the case went to court.