The Department of Justice didn't say which third party helped it hack the iPhone; however, it's likely Cellebrite, an Israeli company.
"The FBI has now successfully retrieved the data stored on the San Bernardino terrorist's iPhone and therefore no longer requires the assistance from Apple required by this Court Order," DOJ spokeswoman Melanie Newman said in a statement.
The DOJ has decided to drop its case against Apple in this instance, since it no longer needs the company's help.
The method used apparently only works on this particular model running iOS 9, so it's unclear whether the DOJ plans to withdraw its case against Apple in New York.
Apple had refused to help the FBI build a backdoor into the iPhone and was set to face off against the agency in court when the Justice Department postponed the hearing after a third party demonstrated a method of unlocking the device.
It's unlikely that this is the end of the battle over the security and privacy of our smartphones. Please follow iClarified on Twitter, Facebook, Google+, or RSS for updates.