How does fake news spread?

He has been misidentified as the lone gunman in the shootings in San Bernardino, in Kalamazoo, in Baton Rouge, in Orlando and, now, in Sutherland Springs, Texas.

His name is Sam Hyde. And he's actually a comedian.

But somehow, his name has become an internet meme, resurfacing after nearly every mass shooting in the past few years.

This time, it was a Congressman Vicente Gonzalez of Texas who fell for the hoax, telling CNN on Sunday, that the name “he was given” for the gunman was Sam Hyde.

Tim Squirrell, a researcher at the University of Edinburgh, studies how misinformation like this spreads on the internet.

It happens, he says, “incredibly rapidly,” and once the fake news gets picked up, “it’s almost impossible to tamp down.”