It's the kind of news scoop that every journalist and news outlet dreams of reporting first. But it wasn't one of the "big boys" who proclaimed the news of the death of Osama bin Laden; it was a 15-word tweet on Twitter.

A previously little-known former White House staffer was the first to report that bin Laden was dead, though he may not have realized the import of what he was doing at the time.

Keith Urbahn, the former chief of staff for Donald Rumsfeld, the former U.S. defence secretary under President George W. Bush, was the one who leaked one of the biggest news scoops of the century. And the media outlet he used to reveal the news wasn't a respectable news agency or newspaper; it was himself, through Twitter.

After the White House announced suddenly just before 10 p.m. ET Sunday night that the President of the United States would address the world in 30 minutes, Twitter erupted in speculation.

What could prompt the president to hold a news conference at that time of night with that little notice, Twitter users began asking. Was it about something in the Mideast? Libya? Perhaps the death of Moammar Gadhafi?

Twitter was immediately overrun by #ObamaGuesses. But while reporters tried to work their sources and find out what was going on, it was Urbahn who revealed the news in a 79-character tweet.

At 10:25, Urbahn tweeted: "So I'm told by a reputable person they have killed Osama Bin Laden. Hot damn."

Within minutes, Urbahn appeared to step back a bit, tweeting next: "Don't know if its true, but let's pray it is" and then: "Ladies, gents, let's wait to see what the President says. Could be misinformation or pure rumor."

If the tweet had come from someone less reliable, Urbahn's tweets may have disappeared into the cyberspace either.

But Urbahn's close White House connections could not be ignored, and his missive sent news outlets into a tizzy. Though it would take 20 minutes, U.S. new outlets began announcing that "reports say" that the big news that Obama was about to announce was bin Laden's death.

How Urbahn got his information remains unclear. Some speculate that his "reputable person" may have been Rumsfeld himself, who had heard it from Bush, who had been phoned by Obama ahead of the public announcement.

Interesting then, that with just one phone call, Obama may have "scooped" himself. Because it would be a full hour and 10 long minutes before Obama addressed the cameras in what turned out to be a rather anticlimactic news conference.

By then, everyone already knew the news. Indeed, many on Twitter joked in the minutes before the announcement that Obama would begin his news conference by saying, "Just go read Twitter."

Interestingly, Urbahn may not have the very first to report the news. Instead, it may have been an IT consultant living in Abbottabad, Pakistan, who first reported the attack on Twitter – seemingly unwittingly.

At about 3.30 p.m. ET on Sunday, Sohaib Athar, who uses the Twitter handle "ReallyVirtual", first tweeted about a helicopter hovering above him in the middle of the night.

"Helicopter hovering above Abbottabad at 1AM (is a rare event)," he wrote.

Within minutes, he again tweeted: "A huge window shaking bang here in Abbottabad Cantt. I hope its not the start of something nasty :-S". With a few more tweets, he suggests the attack and firefight lasted just a matter of minutes.

Athar then appeared to go back to sleep, since his tweets stopped. He awoke the next morning amid rumours that bin Laden had been killed nearby: "interesting rumors in the otherwise uneventful Abbottabad air today," he tweeted. And then, in a retweet from Munzir Naqvi: "I think the helicopter crash in Abbottabad, Pakistan and the President Obama breaking news address are connected."

Within a few hours, Athar realized what his tweets had done: he had made himself a Twitter celebrity. Around 1 a.m. ET, he tweeted, "Uh oh, now I'm the guy who liveblogged the Osama raid without knowing it." and then: "and here come the mails from the mainstream media... *sigh*".

His tweets then suggest that his email has filled with media requests for interviews -- as well as notifications of new Twitter followers. According to twittercounter.com, Athar had around 750 followers as of April 30. Today, he has more than 29,000 -- and counting.

His latest tweet to date: "Bin Laden is dead. I didn't kill him. Please let me sleep now."