NEW YORK – For about an hour Wednesday afternoon, people could flip through different television channels and hear completely different accounts of the investigation into the Boston Marathon explosions: Some news organizations reported the arrest of a suspect and then took those claims back.

CNN, Fox News Channel and the Boston Globe said that a suspect in Monday’s bombing had been arrested. The Associated Press said a suspect had been taken into custody. Within an hour, the FBI denied that a suspect had been captured, leading the three news organizations that had reported the arrest to back down from those claims.

The AP, while reporting the federal denial, said that its original source was standing by its claim that a suspect had been taken into custody. The news cooperative said its source was a law enforcement official speaking on condition of anonymity. By nightfall, with no evidence that anyone was in custody, the original source was unable to further explain what was going on.

ABC, CBS and NBC all broke into their regular programming to report progress in the case, but did not say there was an arrest or someone brought into custody.

The frantic afternoon presented another example of news organizations being embarrassed by a race to report information under intense competitive pressure. It was reminiscent of the day last year that the Supreme Court handed down its decision on President Obama’s health care plan, when both CNN and Fox initially got the ruling wrong in their haste to report it.

In Wednesday’s scenario, CNN’s John King had jumped out early around lunchtime, saying that a department store’s surveillance camera had helped law enforcement spot a person dropping a container on the street that was believed to be the second of two bombs that detonated near the race’s finish line.

King reported at 1:45 p.m. that an arrest had been made. The Boston Globe tweeted the same thing at 1:53, attributing it to an unnamed official. Six minutes later the Globe sent out a second tweet, saying CNN was the source of its arrest report. Fox News Channel’s Megyn Kelly said at 1:55 that the network had been told of an arrest.

The Associated Press sent out a NewsAlert at 1:53 saying that an arrest was imminent. At 2:14, the AP said a suspect had been taken into custody, but did not say there was an arrest.

The three biggest broadcast networks jumped into the story with cautious reports of progress within five minutes of each other shortly before 2 p.m. NBC reporter Pete Williams was insistent that news organizations reporting an arrest had jumped the gun.

“From the beginning of this, this has been the hallmark of this story — information going in totally different directions coming from normally very reliable sources,” Williams said. “We can’t just flip a coin on this.”

At 2:15 on MSNBC, Williams said that “at the end of the day, somebody is going to be right, because every news organization is reporting something different.”

King’s exclusive then began to be shot down by three different CNN reporters giving their own on-air reports.

As Chris Cuomo was saying on the air that “we don’t know what’s right or not right at this point,” the onscreen crawl was still reporting that an arrest had been made.

On Fox, Kelly was dialing back that network’s arrest claim, noting the conflicting reports. At 2:15, Kelly told viewers that two law enforcement officials had told Fox there had been an arrest.

“Other news outlets — some are reporting that an arrest has been made and some are reporting that that is not the case,” she said. “Here’s the truth: We don’t know … We just want to be transparent with you on the information that is coming in a breaking news situation that seems to be anything but clear at this moment.”

The Globe at 2:40 p.m. reported that both the U.S. attorney and Boston police said there was no arrest.

The FBI statement denying the arrest, which was transmitted on the AP wire at 2:59, quieted the television chatter.

Amid the confusion, the Columbia Journalism Review offered a one-word tweet: “Sigh.”