(WASHINGTON, AP) — FBI Director James Comey has hinted that the FBI paid more than $1 million to break into the locked iPhone used by one of the San Bernardino attackers.

At an Aspen Security Forum event in London on Thursday, Comey said the FBI had paid an unidentified third-party more money than he’ll earn in his remaining seven years as FBI director.

He did not reveal the precise amount.

The Justice Department last month revealed that an outside entity had approached it with a method that could hack into the phone used by Syed Farook, who along with his wife killed 14 people in the December attacks before dying in a police shootout.

Federal officials have said that the method was successful, though they haven’t revealed what it was.