ABC correspondent Brian Ross speaks on "Good Morning America" in November 2015. The veteran newsman was suspended Saturday for four weeks without pay after an erroneous report on Michael Flynn. (Fred Lee/ABC via AP)

In 2006, ace ABC News investigative reporter Brian Ross went on the air with a big scoop: Pakistani officials, he reported, had arrested Matiur Rehman, an al-Qaeda explosives expert who kept an “official” list of terrorist recruits. Ross suggested the arrest could lead to Osama bin Laden, the al-Qaeda leader who was a fugitive at the time.

One problem: Rehman hadn’t been arrested. A Pakistani foreign ministry official denied the story, calling it “fictitious.” ABC retracted it.

A few months earlier, Ross had had another exclusive: House Speaker Dennis Hastert was under FBI investigation for bribery in the Jack Abramoff lobbying scandal.

Only that wasn’t clear either. In an unusual move, the Justice Department issued public statements denying any federal probe of Hastert, who demanded a retraction and threatened to sue ABC. The network’s veteran reporter stood by his story but later conceded, “it’s really a question of semantics” about the meaning of “under investigation” (Hastert was indicted and convicted in 2015, but in a completely unrelated matter).

All journalists make mistakes, but Ross’s blunders have often been spectacular — and unusually plentiful for someone of his prominent status in broadcasting.

On Friday, Ross caused an uproar with another errant report. This time, he reported that Michael Flynn, President Trump’s former national security adviser, was prepared to testify that Trump had ordered him to contact Russian officials before the election, an admission that, if accurate, would be tangible evidence of collusion between the Trump campaign and a hostile power. Shortly after his report was published, the stock market took a brief but sudden dive, which may have been triggered by the Flynn news.

But later in the day, Ross read a “clarification” on “World News Tonight”: Trump, he said, had asked Flynn to speak with the Russians after the election, when Trump was president-elect, and their discussion concerned joint antiterrorism efforts. Under intense criticism, ABC upgraded the “clarification” to a full-fledged correction on Saturday for what it termed a “serious error.”

It also suspended Ross without pay for a month, an apparent first in his 46-year television career.

Among the many who eagerly pounced on Ross and ABC was Trump, who tweeted mock congratulations to the network for Ross’s suspension. The president also urged people who lost money in the stock market on Friday to sue ABC for the false report.

Ross has broken a number of big stories during his long career at NBC and ABC, including the congressional page scandal involving Rep. Mark Foley (R-Fla.) in 2006. He has been the lead reporter on stories that have won television journalism’s highest honors — Emmys, Peabodys, Polks, Overseas Press Club Awards — multiple times.

But he’s also had more than his share of high-profile clunkers.

In 2001, for example, he reported that the anthrax used in deadly attacks in Washington and New York was coated with bentonite, a chemical compound found only in biological weapons manufactured by Saddam Hussein’s regime in Iraq. He was wrong. The FBI subsequently reported that there was no bentonite present in the poison that killed five and that it was manufactured domestically. The agency’s chief “person of interest” was an American researcher, Bruce Ivins, who committed suicide in 2008 before he could be charged.

At the start of the Iraq War in 2003, Ross reported that Ali Hassan al-Majid, an Iraqi general known as “Chemical Ali” for his gas attacks on Iraqi Kurds, had been killed in American airstrikes. But six months later, Pentagon officials announced that Chemical Ali was alive and in American custody. He was executed in 2010.

Ross came under attack, especially among conservatives, in 2012 when he mistakenly reported that the suspect in the mass shooting at an Aurora, Colo., movie theater was a member of the tea party movement. Ross based his inaccurate report about the suspect, James Holmes, on a Web page that listed “Jim Holmes” as a member of the Colorado Tea Party Patriots. Ross later apologized for the mistake.

The false Holmes report bears an unfortunate similarity to Ross’s Flynn reporting in at least one way. In both cases, ABC said Ross reported the news before it was “fully vetted.” It did not explain what it meant.

But a former network news producer said ABC shared some of the responsibility for Ross’s errors because it gave him “excessive deference” due to his awards and seniority.

“He was given a long leash,” said the former journalist, who spoke on the condition of anonymity because he didn’t want to publicly criticize a longtime competitor. “With other reporters, these kinds of mistakes would be career-ending. He had nine lives.”

He added, “Brian always needed a strong editor as a final check on his work. ABC never really figured that out. He’s made so many mistakes that at a certain point, deference should have given way to sanity, and someone at ABC should have said, ‘We need a strong, independent person to make sure he’s right.’ Someone to say, ‘Who are your sources, how do they know that, demonstrate their veracity to me.’ ”

ABC News said on Monday that it would have no further comment on Ross. A spokeswoman said he was not available for comment.

Tim Graham, director of media analysis for the Media Research Center, a conservative watchdog group, characterized Ross’s misreporting as a symptom of both increased media sensationalism and liberal bias. ABC’s primary news programs, “Good Morning America” and “World News Tonight,” he said, have become lighter on substance over the years, with diminished interest or investment in investigative reporting.

But Graham said Ross’s latest mistake was most telling for its implied politics. “It comes from the ardor to get Trump,” he said. “The belief that Trump is uniquely dangerous is what creates the sort of atmosphere where [journalists] get reckless and they get ahead of themselves. There’s a fever going around to get rid of Trump. . . That’s what causes this.”