The FBI paid a one-time fee to a group of hackers to help break into one of the San Bernardino shooter’s smartphone, a Washington Post report revealed Tuesday. The hackers allegedly contacted the FBI with a previously unknown iPhone software exploit. That insight was then used to create a piece of hardware to help the bureau crack the four-digit personal identification number on Syed Rizwan Farook’s iPhone’s without triggering a security feature that wipes the data stored on the device, the Post reports, citing people familiar with the matter. The bureau did not enlist Israeli firm Cellebrite for help, as some media reports suggested, sources told the Post. Though FBI Director James B. Comey has previously said the recent hack only works on iPhone 5C models running the iOS 9 operating system, the agency must now decide whether to share the flaw with Apple.