In the rush to find out information about the Connecticut school shooter, numerous media outlets misidentified Facebook pages, including a man with the same name and the killer's brother.
Adam Lanza, 20, gunned down 20 school children and six female staff at the school, before turning the gun on himself on Saturday. He had earlier fatally shot his mother.
Shortly after the story first broke, news reports surfaced referencing a Facebook page attributed to Ryan Lanza, the name initially believed to be that of the gunman.
Police first floated the name after finding an ID bearing that name on the gunman's body, reports AFP.
However, in a further development to the horrific events of Saturday, Ryan Lanza, 24, had to turn to his Facebook page to declare his innocence just after discovering that his mother was dead and his brother was a killer.
"I'm on the bus home now it wasn't me" and "It wasn't me I was at work it wasn't me," wrote Ryan Lanza.
While most websites deleted the photos of wrongly accused man, thousands of people had already shared the image on a range of social media outlets.
Soon after, US media reporters swarmed the home of another Ryan Lanza in New Jersey, and a Twitter user with the name @Ryan_Lanza went from a handful of followers to several thousands within hours.
"So apparently I'm getting spammed bc someone with the same name as me killed some people," he wrote.
Meanwhile, an Adam Lanza of Hustons Mill in Pennsylvania was also the target of media attention.
"Wrong Lanza family, I am not related in any way to the shooter in CT," he wrote on his Facebook page.
Facebook has not commented on the mix-up. However, many users quickly took to Twitter to apologise for the mistake.
"Mistaken identity is toxic when amplified by social media. False accusations not easily scrubbed from the record," wrote Damian Thompson.
While Julia Johnstone tweeted, "So Adam Lanza, stole his brother's identity, I feel so sorry for Ryan, he's lost his mom, dad, brother and the world practically hates him."