James Martin/CNET

The FBI reportedly hasn't found anything helpful on the now-unlocked iPhone tied to the San Bernardino terror attack.

The law enforcement agency is still analyzing information from the Apple iPhone 5C used by Syed Farook, CBS News reported Wednesday. Farook was one of two shooters involved in the December attack that left 14 people dead.

The iPhone was at the center of a legal back-and-forth between the government and Apple earlier this year. The government wanted Apple to write new software that would unlock the phone and make its data readable. Apple refused, saying that weakening the encryption would potentially leave other iPhone users at risk.

Many technology companies and privacy advocates sided with Apple. Law enforcement officials argued that encryption hinders criminal investigations.

The government eventually turned to an unnamed third party to unlock the phone.

The technique used to unlock the iPhone hasn't been divulged publicly and may never be, according to Obama administration sources cited in a Reuters story Wednesday. The third party that created the method for unlocking the phone is the legal owner of the process, according to the report.

The administration uses a procedure called the Vulnerabilities Equities Process to review technology flaws and determine which ones should be made public. However, that process doesn't cover flaws found by private companies so the third party in this case is under no obligation to reveal how it hacked into the phone, Reuters reported.

The FBI itself may not even know how the method worked, government sources told Reuters, so it can't spill the beans either.