Jokes April Fools
In 1986 Israel Radio broadcast that Nabih Berri, leader of the Shi'ite Amal movement, had been assassinated.
The news caused an immediate flare-up of tensions in the region. However, Israeli officials quickly denounced the report as a hoax.
The false report was traced back to an army intelligence officer who had planted the news item in the broadcasts of the Israeli Army's intelligence monitoring unit, from which it had been picked up by Israel Radio.
Apparently the officer had meant it as an April Fool's joke (because hey, nothing says funny like stirring up tension in the Middle-East). Israel's Defence Minister, Yitzhak Rabin, announced that the unnamed officer would be court-martialed. "Berri Berri funny," one foreign correspondent wryly commented.
In the category of 'really bad fake death reports' one must also note the time in 1998 when Boston DJ's Opie and Anthony announced that the mayor of Boston, Tom Menino, had died in a car crash.
Because City Hall couldn't immediately reach the Mayor to confirm that he was actually alive, many believed the report, including members of the Mayor's family. The next day Opie and Anthony were suspended without pay.