It wasn't simply a media error, the recovery crew knew that there were 13 people, and they had found one dead. They went alon further and heard moaning underground, and figured that it was the 12 people (which is also how they knew where to look). The guy reporting it got a bit ahead of himself at the church and said that all 12 were alive, word spread to the media and such. When they went and dug down to the moaning, it turns out that there was only 1 person moaning, the others were dead.
This story can say hello to Last Laugh '06