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Around 9:40 GMT on Saturday morning the phrase “RIP Nelson Mandela” began trending worldwide on Twitter, sparking a wildfire of tweets about his status as dead or alive. This is not the first time death hoaxes have surfaced on Twitter, but it was the first time I noticed one early enough to analyze it to try to find out how it happened.

So I grabbed all of the still existing tweets about Mandela from this weekend and started digging. Below is a timeline of over 6,000 tweets about Mandela from this weekend I captured to analyse.

The first thing I found was that the first person to use the phrase was the user “lebolukewarm” who has since deleted his Tweet, but not before it was retweeted at least 71 times in a few minutes. While he wasn’t the first to tweet about it, it appears that lebolukewarm was the cause of the rumor’s “tipping point” on Twitter. This may undermine traditional ideas about “influential” users as lebolukewarm has barely more than one thousand followers.

Lebolukewarm’s original Tweet happened around 8:40 GMT, an hour before the phrase trended, and between 8:28 and 8:40 several other users, most from South Africa, reported receiving a broadcast Blackberry Messenger (BBM) notice that Mandela had died. One user posted a screen shot of the message.

I talked to Sasha Mitchell, one of the people in South Africa who received the message, and she told me one of her friends sent a broadcast message asking if the rumor was true because she had gotten a BBM from someone else.

I also talked to Lebolukewarm himself and he was kind enough to send me the original BBM he recieved (the source of that BBM got it from someone else and asked to remain anonymous).

Sasha said she believed the original message was an intentional hoax, because any well intentioned person would have researched the rumor before broadcasting it. She also told me that most of her BBM contacts also got the same message, followed by one shortly after that said “He just had a heart attack but he is fine, pls resend to everyone!!!”

A rumor about Justin Bieber dying also emerged on Saturday, and some users reported having also received a BBM about it as well. Early in 2010, McAfee reported that a loophole in a version of the BBM software allows users to add contacts that they don’t really know, opening the door for spam and hoaxes like this.

It appears that while the Mandela rumor was started by some anonymous individual spamming Blackberry users, the real tipping point came when the meme jumped to Twitter and a single user was the vector for that jump.