With little fanfare, federal prosecutors on Friday dropped their investigation of Lance Armstrong, nearly two years after it began. After convening a grand jury, summoning dozens of witnesses and involving several federal agencies, the government decided not to bring fraud and conspiracy charges against Armstrong stemming from allegations that he used performance-enhancing drugs during his legendary cycling career.

While something less than a complete exoneration of Armstrong, the muted end of the investigation raises questions about the media: Did they go too far in painting a picture of misfeasance and illegal behavior by the seven-time Tour de France winner? And did they fail to ask some tough questions about the government’s case?

If you read or heard media accounts of the investigation in 2010 and 2011, the case against Armstrong sounded almost airtight.

“Federal prosecutors are seeking an indictment by January,” the New York Times reported in September 2010, citing “those close to the investigation.”

A few months later, ESPN.com reported: “The U.S. Attorney’s Office in Los Angeles could seek an indictment on fraud and conspiracy charges, possibly within the next few months, sources have said.”

Even as recently as last month, some were predicting the end was near. Sportswriter Selena Roberts, the author of an accusatory Sports Illustrated cover story on the Armstrong case last year, suggested the indictment could come “before or maybe right after the Super Bowl.”

Well, no, as it turned out.

The fact that journalists got it wrong was cold comfort to Armstrong’s camp, which complained for many months about what it saw as one-sided treatment by the news media.

“I think what one sees over and over again is the phenomenon of the story that is too good not to be true,” said Robert Luskin, one of Armstrong’s attorneys. “The [accusations] are so juicy that reporters become unwilling to exercise independent judgment. They become seduced by their sources and take too much at face value. No one stops and says, ‘That doesn’t sound right to me.’ ”

While that is plainly a partisan view, the Armstrong case does seem to share some elements with other recent stories in which reporters relied on leaked information from one side and flawed accusers to construct an unflattering or accusatory narrative.

The drip of damning evidence against Armstrong looks like a slow-moving version of the sexual assault allegations last year against international banker Dominique Strauss-Kahn or the rape accusations in 2006 against members of the Duke lacrosse team. In both of those cases, prosecutors withdrew their charges, concluding that the widely reported accusations were untrue or wouldn’t stand up in court. (In the Duke case, the prosecutor was disbarred for his misconduct.)

Although cycling has been tainted by drug scandals for years, Armstrong vehemently denied taking performance-enhancing drugs during his long career, a statement noted in most media accounts. He cited more than 500 “clean” drug tests stretching back nearly 15 years, making him perhaps the world’s most drug-tested athlete.

But Armstrong and his supporters were on the defensive from the moment a former teammate, Floyd Landis, went public in May 2010 with accusations that Armstrong had used drugs during his tour victories and “encouraged” teammates to do the same. A second accuser, Tyler Hamilton, went public a year later, appearing on “60 Minutes.”

As the federal investigation heated up in 2010, Armstrong’s camp objected repeatedly to leaks to the media that made it sound as if investigators were building a powerful case against him. They also protested that Hamilton and Landis weren’t credible; both men had lied about their drug use for years before being stripped of their racing titles amid failed tests. Both were also peddling books about their experiences.

The New York Times published numerous articles about the probe, including three reports on its front page in mid-2010. One piece, in August, reported that unnamed cyclists “have supported and detailed claims that Armstrong and his former [teammates] participated in systematic doping.”

A subsequent Times article reported that “people inside Lance Armstrong’s inner circle of friends and colleagues are being called to testify in front of a grand jury investigating suspected doping and fraud in professional cycling, raising the intensity of the inquiry.”

Luskin, who defended Karl Rove in the leak of CIA officer Valerie Plame’s identity, said such stories are invariably favorable to the prosecution in a case because they “create the appearance of momentum” in an investigation. By keeping an investigation’s profile up in the news media, he said, prosecutors and investigators hope to flush out witnesses or prevent their superiors from shutting down a weak or questionable case.

But Bill Keller, the editor of the Times during the height of the Armstrong stories, has no regrets. “He was a uniquely towering figure in a sport that has long been under a cloud,” Keller said in an e-mail, noting Armstrong’s prominence as an athlete and cancer survivor and fundraiser. At the time, he added, two anti-doping agencies were also looking into Armstrong. “None of that makes Armstrong guilty of anything, but investigations of that magnitude are stories — big stories,” he wrote.

Keller said the Times sought out “all sides of the story” and regularly pointed out Hamilton’s and Landis’s checkered pasts.

The Washington Post was more restrained in its reporting than the Times, ESPN.com and a handful of other outlets that covered the Armstrong investigation on a nearly full-time basis. The newspaper ignored several alleged developments in the case and confined its coverage to its Sports pages. But the paper did report on the investigation at important junctures. In mid-2010, it reported, for example, that “at least two people have corroborated some of Landis’s sweeping claims regarding doping, according to an individual with knowledge of the investigation.

Some readers and sources, including anti-doping officials, chided The Post for its approach, saying it was too protective of Armstrong. They noted the close ties between Armstrong and Post sports columnist Sally Jenkins. Armstrong and Jenkins have collaborated on two best-selling books, “It’s Not About the Bike” and “Every Second Counts.” But Matthew Rennie, The Post deputy sports editor, said, “We felt our level of coverage was appropriate based on what our reporting told us.”

Those close to Armstrong were especially dismayed that few reporters bothered to question the probe itself.

Given the trouble federal prosecutors had in securing convictions after the investigations of baseball players Barry Bonds and Roger Clemens for alleged steroid use, they suggested that the investigators should have been treated more skeptically.

Among the few reporters who did was the Associated Press’s Pete Yost, who reported last February that “the federal investigation has encountered serious hurdles.” Citing “lawyers familiar with the matter,” Yost pointed to weaknesses in the government’s case: that Armstrong had never failed a drug test; about whether forensic evidence existed that could be used against him; and about whether Landis — the only person to say he saw Armstrong doping — had sufficient credibility to persuade a jury.

“The only certainty is that it will be quite a while before the Armstrong probe ends,” Yost wrote, accurately as it turns out.