There were many who figured the news was either major developments in Libya (Gaddafi killed) or that Osama Bin Laden had been killed or captured. The first reliable source came from Keith Urbahn, spokesman for former Secretary of Defense Donald Rumsfeld who served under George W. Bush from 2001 to 2006.
Soon after Urbahn's tweet, major networks began to report
that the statement by the President would address the death of Osama Bin
Laden. First CBS, then Fox News and then NBC.
First paper online to report death of Bin Laden appeared to be the New York Times.
Reuters came soon after the New York Times
CNN was careful and was one of the last, if not the last network to report that Bin Laden had been killed.
On air, CNN reported some of the first details of how the operation took place.
At this point crowds began to gather in front of the White House to celebrate the news.
Reuters reported that U.S. special forces carried out the attack.