FBI Director James Comey said Wednesday that the government had purchased "a tool" from a private party in order to unlock the iPhone used by one of the San Bernardino shooters.

"Litigation between the government and Apple over the San Bernardino phone has ended, because the government has purchased, from a private party, a way to get into that phone, 5C, running iOS 9," Comey said.

Law enforcement officials revealed in late March that they had finally cracked the iPhone used by Syed Farook, one of two shooters in the December 2015 attack that left 14 people dead. But they did not go into details, other than to say an unnamed third party had provided assistance.

In an effort to access information stored on his phone, the government had pursued legal action in order to force Apple to help bypass the phone's security features.

Related: FBI says it has cracked terrorist's iPhone without Apple's help

Apple (AAPL) declined to assist, saying that to do so would compromise the security of all iPhone users. The company argued that law enforcement officials didn't understand the consequences of creating a backdoor into the phone.

After the case was dropped, speculation swirled as reporters and analysts tried to identify the third party that helped the government unlock the phone.

Comey revealed additional information about the source of the tool Wednesday.

"The people we bought this from, I know a fair amount about them, and I have a high degree of confidence that they are very good at protecting it, and their motivations align with ours," he said.

Related: Will FBI have to tell Apple how it hacked terrorist's iPhone

The FBI director also said the purchased tool worked only on a "narrow slice of phones" that does not include the newest Apple models, or the 5S.

Comey said the government was currently considering whether to tell Apple how it pulled off the hack.

"We tell Apple, then they're going to fix it, then we're back where we started from," he said. "We may end up there, we just haven't decided yet."