“When The New York Times reported in April that a contractor had purchased and deployed a spying tool made by NSO, the contentious Israeli hacking firm, for use by the U.S. government, White House officials said they were unaware of the contract and put the F.B.I. in charge of figuring out who might have been using the technology. After an investigation, the F.B.I. uncovered at least part of the answer: It was the F.B.I.”
Source : Who Paid for a Mysterious Spy Tool? The FBI, an FBI Inquiry Found. – The New York Times