Questions remain about how privacy will be affected in the future, and what will happen the next time the US government is frustrated by digital security lockout features.
Government prosecutors have asked a federal judge to vacate a disputed order forcing Apple to help the FBI break into the iPhone, saying it was no longer necessary.
The FBI used an unspecified technique to access data on an iPhone belonging to gunman Syed Farook, who died with his wife in a gun battle with police in San Bernardino, California, in December. The Farooks had earlier killed 14 people.
The US justice department said agents are now reviewing the information on the phone.
The government’s brief filing, in the US district court for the Central District of California, provided no details on how the FBI got into the phone.
Nor did it identify the non-government “outside party” who showed agents them how to do so.
Authorities had previously said that only Apple could help them unlock the phone.
Apple said it will continue to increase the security of its products.
“We will continue to help law enforcement with their investigations, as we have done all along,” a spokesperson the company said, while reiterating its argument that the government’s demand for Apple’s help was wrong. “This case should never have been brought.”
FBI assistant director David Bowdich said that examining the contents of the iPhone was part of the authorities’ effort to learn if the San Bernardino shooters had worked with others, or had targeted any other victims.
“I am satisfied that we have access to more answers than we did before,” he said.
The dispute ignited a fierce debate about digital privacy rights and national security concerns and the impact of encryption on law enforcement’s ability to serve the public.
Californian representative Darrell Issa said that while it is “preferable” that the government has gained access to the iPhone without Apple’s help, the question of the extent to which the government should be able to access personal information remains unanswered.
Mr Issa, a Republican critic of the administration’s domestic surveillance practices, said the government’s legal action against Apple raises constitutional and privacy questions and that “those worried about our privacy should stay wary”, because this does not mean “their quest for a secret key into our devices is over”.
The surprise development punctured the temporary perception that Apple’s security might have been good enough to keep consumers’ personal information safe even from the US government.