Google and Facebook have apologised after their algorithms led to the promotion of inaccurate information about the Las Vegas shooting.
Posts from a 4chan messaging board that falsely identified the gunman as an individual who was not involved were circulated online.
Google says the posts only appeared in its Top Stories section if users searched for the erroneous name.
Facebook said it took down the posts within minutes.
Speculation gone viral
The problem occurred when users began speculating about the identity of the gunman on 4chan, a controversial anonymous messaging board.
The users named an individual on the Politically Incorrect message board, claiming that the person was a "far left loon" and a "social democrat".
The comments were picked up by several blogs and news sites, including an article by the right-wing political website, the Gateway Pundit.
Many users then searched for the erroneous name on Google. The internet giant's algorithms traced the original source of the story back to the 4chan message board and posted a link to it in the Top Stories section.
"Unfortunately, early this morning we were briefly surfacing an inaccurate 4chan website in our search results for a small number of queries," a Google spokesperson told the BBC.
"Within hours, the 4chan story was algorithmically replaced by relevant results. This should not have appeared for any queries, and we'll continue to make algorithmic improvements to prevent this from happening in the future."
However, Google said only a small number of search queries were made for the name, which suggests that not many people would have seen the 4chan link.
As for Facebook, the social network told the Associated Press that it began removing results relating to the Gateway Pundit and 4chan within minutes.
The Gateway Pundit's White House correspondent Lucian Wintrich told far-right conspiracy website Infowars that the article was only online for 10 minutes before it was taken down.
Despite Facebook's efforts to remove hyperlinks to the story, users had made screenshots of the incorrect story and continued to circulate these images online, which were harder to detect and take down.
"We are working to fix the issue that allowed this to happen in the first place and deeply regret the confusion this caused," a Facebook spokesman said.
Credit: bbc.co.uk
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