By MICHAEL ISIKOFF

The FBI inadvertently revealed one of the U.S. government’s most sensitive secrets about the Sept. 11 terror attacks: the identity of a mysterious Saudi Embassy official in Washington who agents suspected had directed crucial support to two of the al-Qaida hijackers.

The disclosure came in a new declaration filed in federal court by a senior FBI official in response to a lawsuit brought by families of 9/11 victims that accuses the Saudi government of complicity in the terrorist attacks.

The declaration was filed last month but unsealed late last week. According to a spokesman for the 9/11 victims’ families, it represents a major breakthrough in the long-running case, providing for the first time an apparent confirmation that FBI agents investigating the attacks believed they had uncovered a link between the hijackers and the Saudi Embassy in Washington.

It’s unclear just how strong the evidence is against the former Saudi Embassy official — it’s been a subject of sharp dispute within the FBI for years. But the disclosure, which a senior U.S. government official confirmed was made in error, seems likely to revive questions about potential Saudi links to the 9/11 plot.

It also shines a light on the extraordinary efforts by top Trump administration officials in recent months to prevent internal documents about the issue from ever becoming public.

“This shows there is a complete government cover-up of the Saudi involvement,” said Brett Eagleson, a spokesman for the 9/11 families whose father was killed in the attacks. “It demonstrates there was a hierarchy of command that’s coming from the Saudi Embassy to the Ministry of Islamic Affairs [in Los Angeles] to the hijackers.”

Still, Eagleson acknowledged he was flabbergasted by the bureau’s slip-up in identifying the Saudi Embassy official in a public filing. Although Justice Department lawyers had last September notified lawyers for the 9/11 families of the official’s identity, they had done so under a protective order that forbade the family members from publicly disclosing it. (Text, excluding headline, courtesy of Yahoo News)