22 people were killed in the shooting in El Paso, Texas

Hundreds of miles away from Saturday's mass shooting at a Walmart in Texas, an Alabama man received a wave of death threats on social media because he has the misfortune of sharing a name with the man suspected of slaying 22 people in El Paso.

"I've got two young kids at the house. I'm worried for our safety and our safety in our home," said Rebecca Calla Toulmin, speaking for her fiance, Patrick Crusius, a 33-year-old salesman from Montgomery, the state's capital city.

Crusius' namesake is the 21-year-old who police say travelled about 650 miles from his hometown in Allen, Texas, to El Paso, where he opened fire indiscriminately.

Meanwhile, Connor Betts, an 18-year-old in Cleveland, was living an identical nightmare to the Alabama man. Betts was mistaken for another suspected gunman, also named Connor Betts, who is accused of carrying out a mass shooting in Dayton, Ohio, hours after the El Paso massacre.

"I'm not him," Betts said in a post on Facebook. "So please stop misidentifying me for him. I'm no way shape or form associated." He did not respond to a request for comment.

With misinformation and rumours spreading unchecked through social media, cases of mistaken identity have become all to common in mass shootings.

A Florida teenager who shares his name with Nikolas Cruz, the suspect in the killing of 17 students and staff at Marjory Stoneman Douglas High School in Parkland, Florida, wants to change his name, his mother told the Sun Sentinel newspaper.

She said he is tired of people recoiling at the sound of his name and that he is no longer proud of it.

A man who shared a name with James Holmes, who killed 12 people in an Aurora, Colorado movie theatre in 2012, received similar threats.

Following the 2013 mass shooting at Sandy Hook Elementary School in Newtown, Connecticut, law enforcement wrongly identified Ryan Lanza as the gunman. By the time police said the shooter was actually Adam Lanza, Ryan's younger brother, Ryan's picture had been shared thousands of times online.

On Saturday, Crusius and Toulmin had planned on spending quality time together, away from their children. Suddenly, the pair started to receive hundreds of messages on Facebook.

"People were saying that we should die, that our children should die," a shaken Toulmin told Reuters on Monday. "Then we turned on the news and we're just dumbfounded."

Crusius, who was not immediately available for comment, took to Facebook to clear himself.

"Whoa guys!!! I am not the guy you think your looking for!," Crusius said in a post on Saturday. "I have never been to Texas and look nothing like the guy!!!"

But the threats haven't stopped since Saturday, said Toulmin.

The death threats prompted the family to call local authorities for protection. Police have been patrolling around their home, Toulmin said.