— -- Cleveland police are searching for a suspect who they say killed an elderly man and uploaded a video of the killing to Facebook.
The slaying happened at about 2 p.m. Sunday, police said. The suspect, identified by police as Steve Stephens, is described as 6 foot 1, 244 pounds and bald, with a full beard. He was wearing a dark blue and gray- or black-striped polo shirt and is believed to be driving a white Ford Fusion, according to police.
Cleveland police issued a warrant for Stephens on a charge of aggravated murder.
The police said he may already have left Ohio and asked residents of Pennsylvania, New York, Indiana and Michigan to be on alert. Police in Erie, Pennsylvania, confirmed to ABC news early Monday that they were notified of a ping detected from Stephens' cellphone on the east side of Erie County.
In the video, which has since been removed from Facebook, the victim, later identified by police as Robert Godwin Sr., 74, can be seen raising his hands in an apparent attempt to ward off his attacker before he is shot once in the head. Police initially said the victim's last name was spelled Goodwin.
Stephens claims to have committed multiple homicides, according to police. No additional victims have been found, though officers are searching a number of locations, police said.
At a press conference Sunday evening, police urged Stephens to turn himself in.
"Everybody is looking for Steve," said Cleveland Police Chief Calvin Williams, adding that there have been no confirmed sightings of the suspect since the video was posted on Facebook Live.
Williams said the killing is believed to be random.
Stephens is a member of the assertive community treatment team at Beech Brook, a mental health organization in northeastern Ohio, a spokesperson for his employer confirmed.
"We learned about [the shooting] this afternoon, when someone saw it on FB and notified us," said Nancy Kortemeyer, the vice president of marketing and PR at Beech Brook. "We are doing everything we can to help and help locate him."
She added, "We are shocked and horrified."
Joy Lane, who dated Stephens for several years, released a statement offering her condolences to the victim's family.
"My heart and prayers goes out to the family members of the victim(s). Steve really is a nice guy ... He is generous with everyone he knows. He was kind and loving to me and my children. This is a very difficult time for me and my family."
In the video he uploaded to Facebook, Stephens mentions Lane in the moments before the shooting, saying to the victim, "She's the reason why all this about to happen to you."
Stephens is considered armed and dangerous, according to police.
In a statement, a Facebook spokesperson called the incident a "horrific crime" and said that the company does "not allow this kind of content on Facebook."
The spokesperson added that the shooting was not broadcast on Facebook Live but that video of it was uploaded after it took place. The suspect broadcast another video on Facebook Live at one point, the spokesperson said.
"We work hard to keep a safe environment on Facebook and are in touch with law enforcement in emergencies when there are direct threats to physical safety," the Facebook spokesperson added.
The FBI is assisting Cleveland police in the investigation.
This is a developing story. Please check back for updates.
ABC News' Stephanie Wash, Kate Hodgson, Joshua Hoyos and Benjamin Stein contributed to this report.