Residents of Cleveland were on edge as police were searching for a suspect who shot and killed an elderly man and streamed the murder live on Facebook on Sunday (April 16) and later claimed that he had murdered 13 people in all.

The Cleveland Division Police said it was looking for Steve Stephens in connection with the killing of the man, and warned residents that he was armed and dangerous, as area hotels and other establishments went on lockdown, and Cleveland airport heightened security.

"Suspect did broadcast the killing on Facebook Live and has claimed to have committed multiple other homicides which are yet to be verified," the police said in a statement, referring to social-media network Facebook Inc's live-streaming video service.

The killing occured near Cleveland's vibrant arts and medical district, anchored by the sprawling Cleveland Clinic complex and Case Western Reserve University, where officials advised students - many of them from Asia - to be on alert for the suspect.

In the video, which has since been taken down from the social media website, a car door is seen opening as the suspect mutters and swears to himself: "Found me somebody I'm going to kill, this guy right here, this old dude".

The video first shows a cracked pavement then focuses on the shooter approaching an elderly grey-haired African-American man with a goatee in a blue plaid shirt and what appears to be an Ohio State University football cap carrying a plastic shopping bag as he shuffles down the street He was later said to be a 78-year-old man identified only as "Mr Goodwin".

The shooter then asks Mr Goodwin "Can you do me a favour?" The perplexed victim says "What?"

The shooter then asks him what sounds like "Can you say Joy Lane? Can you say Joy Lane?"

"Joy Lane?" the elderly man responds.

Then the shooter says: "Ya. She's the reason why all this might happen to you."

Then he asks "How old are you?" as his victim, realising he is in danger, raises his hand holding the bag in front of his face when the shooter points a gun at him.

Then as he pleads "I don't know, I don't know nobody by that name," a gun can be seen pointed at the man's face and a gunshot heard.

The elderly man jerks backward. The video continues showing him on the ground, the plastic bag partially covering his face, and blood streaming from his head and along the ground.

The shooter then says: "That (expletive) is dead cause of you Joy."

The video then continues showing the large, hulking shadow the man walking calmly back to his car, which police described as a white or cream-colored Ford Fusion.

The bearded, bald Stephens is seen in a striped blue short-sleeve shirt boasting of having killed 13 people and saying he was looking for a 14th victim. Police have only confirmed a single homicide thus far, however.

Cleveland Mayor Frank Jackson later went on television saying: "We want to personally give our condolences to the family of the victim."

Then he urged Stephens that he would be caught and "need not do any more harm to anybody, any innocent people" and that "whatever concerns or problems we have, we're here to have a conversation with him".

In January, four black people in Chicago were accused of attacking an 18-year-old disabled white man and broadcasting the attack on Facebook Live while making anti-white racial taunts. The incident prompted international outrage.

A month later, the accused pleaded not guilty to assaulting the man, whom prosecutors described as schizophrenic.