WASHINGTON — The hackers’ targets: The former head of cybersecurity for the U.S. Air Force. An ex-director at the National Security Council. A former head of the Defense Intelligence Agency.

All were caught up in a Russian government-aligned cyberespionage campaign. None was warned by the FBI.

The bureau repeatedly failed to alert targets of the Russian hacking group known as Fancy Bear despite knowing for more than a year that their personal emails were in the Kremlin’s sights, an Associated Press investigation has found.

“No one’s ever said to me, ‘Hey Joe, you’ve been targeted by this Russian group,’” said former Navy intelligence officer Joe Mazzafro, whose inbox the hackers tried to compromise in 2015. “That our own security services have not gone out and alerted me, that’s what I find the most disconcerting as a national security professional.”

The FBI declined to discuss its investigation into Fancy Bear’s spying campaign, but did provide a statement that said in part: “The FBI routinely notifies individuals and organizations of potential threat information.”

Three people familiar with the matter — including a current and a former government official — said the FBI has known the details of Fancy Bear’s attempts to break into Gmail inboxes for more than a year. A senior FBI official, who was not to authorized to publicly discuss the hacking operation because of its sensitivity, said the bureau had been overwhelmed by an “almost insurmountable problem.”

The AP conducted its own investigation into Fancy Bear, dedicating two months and a small team of reporters to go through a list of 19,000 phishing links provided by the cybersecurity firm Secureworks.

The list showed how Fancy Bear worked in close alignment with Kremlin interests to steal tens of thousands of emails from the Democratic Party, the AP reported this month.

But it wasn’t just Democrats the hackers were after.

The AP identified more than 500 U.S.-based targets in the data, reached out to more than 190 of them and interviewed nearly 80 people, including current or former military personnel, Democratic operatives, diplomats or ex-intelligence workers such as Mazzafro.

Many were long-retired, but about one-third were still in government or held security clearances at the time of the hacking attempts. Only two told the AP they learned of the hacking attempts from the FBI. A few more were contacted by the FBI after their emails were published in the torrent of leaks that coursed through last year’s electoral contest. To this day, some leak victims have not heard from the bureau.

One was retired Maj. James Phillips, who was one of the first people exposed by the website DCLeaks in mid-2016. A year later, Philips has yet to hear anything from the FBI.

In fact he didn’t learn his emails were “flapping in the breeze” until two months after the fact, when a journalist called him to ask for comment.

“The fact that a reporter told me about DCLeaks kind of makes me sad,” Phillips said in a telephone interview.

Phillips’ story would be repeated again and again as the AP spoke to officials from the National Defense University in Washington to the North American Aerospace Defense Command in Colorado.

Among them: a former head of the Defense Intelligence Agency, retired Lt. Gen. Patrick Hughes; a former head of Air Force Intelligence, retired Lt. Gen. David Deptula; a former defense undersecretary, Eric Edelman; and a former director of cybersecurity for the Air Force, retired Lt. Gen. Mark Schissler.

Some targets of Fancy Bear’s spying said they don’t blame the FBI for not notifying them.

“The expectation that the government is going to protect everyone and go back to everyone is false,” said Nicholas Eftimiades, a retired senior technical officer at the Defense Intelligence Agency who teaches homeland security at Pennsylvania State University in Harrisburg and was himself among the targets.

But Charles Sowell, who previously worked as a senior administrator in the Office of the Director of National Intelligence and was targeted by Fancy Bear two years ago, said there was no reason the FBI couldn’t do the same work the AP did.

“It’s absolutely not OK for them to use an excuse that there’s too much data,” said Sowell. “Would that hold water if there were a serial killer investigation, and people were calling in tips left and right, and they were holding up their hands and saying, ‘It’s too much’?

“That’s ridiculous.”

Editor’s note from the AP: Raphael Satter’s father, David Satter, is an author and Russia specialist who has been critical of the Kremlin. His emails were published last year by hackers and his account is on Secureworks’ list of Fancy Bear targets. He was not notified by the FBI.