US Police in Cleveland, Ohio, have recruited authorities from neighboring states as well as the Federal Bureau of Investigation and the US Marshals Service to join the manhunt for 37-year-old murder suspect Steve Stephens. Authorities warned people in the US states of Pennsylvania, New York, Indiana and Michigan to remain vigilant, with the last known location of the suspect being Erie, Pennsylvania - more than 100 miles (160 kilometers) away from the scene of the crime.

Police say that Stephens is wanted for the murder of 74-year-old Robert Godwin Sr, who was shot and killed on Easter Sunday. Stephens had filmed the crime and shared the footage on Facebook before disappearing. Authorities meanwhile warned that the suspect might be armed and dangerous, given that he had threatened to kill again.

"We know that Steve is still out there someplace," Cleveland police chief Calvin Williams said. "We don't know his condition and, of course, right now we don't know his location. We're asking the public to remain vigilant."

"He could be nearby. He could be far away or anywhere in between," FBI agent Stephen Anthony said on the second day of the manhunt. Stephens was described as a six-foot one-inch (1.85-meter), 244-pound (110-kilo) black man with a full beard, who was last seen driving a white Ford Fusion (very similar to the Ford Mondeo available in Europe) with temporary license plates.

Suspect might be serial killer

Police issued an arrest warrant for aggravated homicide against Stephens after a video was uploaded to his Facebook page, in which a man resembling him is seen putting a gun to the head of the victim and firing it. Robert Godwin Sr is seen on the footage falling to the ground after a shot was fired. Early reports said that the crime was broadcast live on Facebook, which later was repudiated.

In a second video, the suspect is seen boasting about a number of murders: "I killed 13, so I'm working on 14 as we speak," the suspect says. Police said they had not yet verified Stephens' claims to have killed others.

Facebook subsequently took down the videos: "This is a horrific crime and we do not allow this kind of content on Facebook," the company 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."

Facebook has come under fire before for not applying sufficient protection to avoid violent acts being shown on it. Earlier in 2017, three people in Sweden broadcast a rape live on the social network. 

Authorities contact suspect

Police said the motive for the shooting of Godwin wasn't entirely clear from the shaky video, but could likely be linked to personal relationship problems. Stephens is seen in the footage telling Godwin a woman's name and saying, "She's the reason that this is about to happen to you."

Godwin did not seem to recognize the woman's name.

Stephens' mother meanwhile told CNN news that she managed to call him after learning about the video. Stephens apparently told her that he was shooting people because he was "mad with his girlfriend."

Police said that the woman Stephens referred to was in a safe place. Detectives from the Cleveland Police Department have also reportedly managed to make contact with Stephens by phone.

"They tried to, of course, convince him to turn himself in and, of course, that hasn't happened to date so again, we're asking the public's help in finding this guy. We know he's out there," Cleveland police chief Calvin Williams said.

Suspect worked with children and youths

Stephens worked at Beech Brook, a behavioral health agency for children headquartered in Pepper Pike, near Cleveland. His job entailed helping young people, including teenagers in foster care and at-risk youths, to develop skills and find employment, according to Beech Brook spokeswoman Nancy Kortemeyer.

"We are shocked and horrified like everyone else," Kortemeyer told CNN. "To think that one of our employees could do this is awful."

Stephens had reportedly undergone an extensive background check before he was hired to work for the company. Kortemeyer said the nothing worrisome had turned up in the checks.

In one of the videos, Stephens was seen holding up his employee identification, saying: "I'm killing with my Beech Brook badge on, too."

ss/msh (AFP, AP)