The iPhone 5c belonging to the San Bernardino shooters is believed to contain evidence which the FBI supposedly managed to obtain by paying professional hackers for unlocking the device.
According to the Washington Post, the FBI managed to unlock the iPhone 5C belonging to the San Bernardino shooter Syed Farook by paying an unnamed group of professional hackers, which they infiltrated the security of the device by using a previously unknown security flaw in the iPhone's software that allowed the FBI to bypass the lockscreen's security feature without compromising the data on the phone.
The hackers are believed to be a "gray hat", a professional security experts for examining software and devices, where they also provide services to search for security weakness in software and hardware that they can utilize and sell them as bugs to government and third-parties.
The security hack that was used to break into the iPhone 5C could only work for that model of Apple's mobile platform running a version of iOS 9, putting users in a fairly limited security issue, according to Mashable.
The FBI has yet to decide whether they will disclose the security bugs to Apple, and if they had to, in a criminal case under the rules of discovery, they would be forced to disclose the information. Last Wednesday at Kenyon College, FBI Director James Comey addressed the issue in a speech on Encryption and Surveillance, "The agency is considering it. It's an interesting conversation because, we tell Apple, they fix it and then we're back where we started from." he said.
It's yet unclear how the security hack works, and whether there were any other agencies or third-parties that bought the flaw from the hackers, but if Apple were not to be informed by it, could put anyone owning an iPhone without fingerprint sensor at risk of having their devices cracked.