FBI Director James Comey (Chip Somodevilla/Getty Images)

The government is pushing back against claims that it misled the public about needing Apple's help to break into an iPhone used by one of the San Bernardino, Calif., shooters.

"We tried everything we could think of -- asked everybody we thought might be able to help inside and outside the government -- before bringing the litigation in San Bernardino," FBI Director James Comey said during a news conference Thursday.

He also wrote a letter Wednesday responding to a Wall Street Journal editorial criticizing the government's handling of the case. "You are simply wrong to assert that the FBI and the Justice Department lied about our ability to access the San Bernardino killer’s phone," Comey said.

Instead, the attention to the case had spurred "creative people around the world to see what they might be able to do" to help the agency get around the phone's security features, he wrote. "Lots of folks have come to us with potential ideas -- it looks like we now have one that may work out. We're optimistic and we'll see," Comey said during the news conference.

On Monday, the Justice Department asked the court overseeing the dispute to delay a hearing set for the next day because an "outside party demonstrated to the FBI a possible method for unlocking" the iPhone in question over the weekend. The government asked for more time to explore if they would be able to use the technique to gain access to the device.

Until then, the government had asserted that it needed Apple's help. "[T]he undisputed evidence is that the FBI cannot unlock [San Bernardino shooter Syed Rizwan] Farook’s phone without Apple’s assistance," it wrote in a March 10 filing about the case.

But Apple disputed that point. In one filing, Erik Neuenschwander, Apple’s manager of user privacy, argued that "past exploits that have bypassed the lock screen and the present-day reality of innumerable security firms, malicious actors, cybercriminals and potential adversaries" made it unlikely that forcing Apple to write software to get around their own security features was the only way to get into the iPhone.

Some outside security researchers and even members of Congress also appeared skeptical that the FBI had explored all of its options before taking Apple to court.

During a House Judiciary Committee hearing at the beginning of the month, Rep. Darrell Issa (R-Calif.) questioned Comey about whether the government had considered a possible solution that would involve making copies of the chip tied to the passcode mechanism and testing different combinations to unlock the phone outside of the actual device. That may, some researchers have suggested, avoid the risk of triggering a security measure that may permanently lock the device if too many incorrect pins are entered.

Comey appeared unfamiliar with the method during his testimony then. Questioned about it on Thursday, he said, "It doesn't work," but that he was "optimistic" that the still unknown strategy that the agency is now testing would be successful.

Issa said in a statement that the hearing postponement raised more questions than answers. "It’s important that the government take all steps possible before asking for wide-reaching powers that would dramatically impact the future of cybersecurity for years to come,” he said.