The suspect, identified as Steve Stephens, fatally shot 74-year-old Robert Godwin, Sr., an apparent random victim, in Cleveland, Ohio, on Sunday.
In a rambling video, Stephens said, "I snapped, I just snapped."
In the video, Stephens blamed a former girlfriend he had lived with, saying he woke up last week and "couldn't take it anymore." But in a statement Monday, the woman shed little light on what might have gone wrong and said Stephens was good to her and her children.
A reward of up to $50,000 for information leading to his arrest was offered Monday.
Stephens is armed and dangerous and should not be approached, police said. He is described as a black man with a full beard. He is 6-feet-1-inches tall and 244 pounds. Stephens was last seen wearing a dark blue and grey or black striped polo shirt.
He is driving a white Ford Fusion with Ohio temporary plates, E363630. Cleveland Police Chief Calvin D. Williams said in a press conference Monday afternoon that there has been no indication that Stephens has changed vehicles.
UPDATE Homicide suspect Steve Stephens' actual vehicle has Ohio Temp tag E363630 pic.twitter.com/tE3r5u4BNN— Cleveland Police (@CLEpolice) April 17, 2017
Williams urged Stephens to contact a relative, friend or pastor. He said authorities want to talk to him and resolve the situation peacefully.
Detectives initially made contact with Stephens via cell phone after the incident was posted, but they were unable to track him or convince him to turn himself in.
Williams said the suspect's last known location was at the scene of the shooting. Police initially said they believed he left Ohio and may be in Pennsylvania, New York, Indiana or Michigan. In an afternoon update, Williams said federal investigators reached out to contacts across the nation to help find Stephens.
Williams said investigators have received "dozens and dozens" of tips, and they are following up on all of them. He encouraged the community to continue to support authorities in the search. An aggravated murder warrant has been issued for Stephens.
As a precaution, officers are working in pairs, police said.
Homicide Suspect ? Armed and Dangerous Steve Stephens https://t.co/uhRGkmyiRU— Cleveland Police (@CLEpolice) April 16, 2017
Though Pennsylvania authorities told CNN early Monday that Stephens' cellphone had issued a "ping," or a signal, in Erie, Pennsylvania, the Erie Police Department said Monday afternoon it had no knowledge of a ping emitted from its city. Erie is about 100 miles east of Cleveland. Williams told reporters Monday he couldn't speak to the report of a ping. Stephens' last known location was the murder scene, he said.
In the video, Stephens got out of a car in a residential area and said, "Here's somebody I'm about to kill. I'm about to kill this guy right here. An old dude."
He walked up, stopped Godwin on the sidewalk and talked to him.
Stephens: "Hi. Can you do me a favor? Can you say Joy Lane?"
Godwin: "Joy Lane?"
Stephens: "Yeah, she's the reason this is about to happen to you."
Then the video showed a gun pointed at Godwin's head. The gun was fired. Godwin recoiled and fell to the ground.
The suspect's mother told CNN that when she last saw Stephens on Saturday, he said it would be a miracle if she ever saw him again. They spoke the next day, she said, and he told her he was shooting people because he was angry with his girlfriend.
Joy Lane issued a statement, saying, "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."
A vigil was held in Cleveland for Godwin Monday night. Dozens of family, friends and community members gathered Monday evening to remember him, carrying flowers and balloons. The hugged and comforted each other, while urging an end to the violence on their city streets.
Stephens is an employee at Beech Brook, a "leading behavioral health agency" in northeast Ohio. He is a member of their ACT (assertive community treatment) team.
Beech Brook said it would be closed Monday and released this statement:
"We were shocked and horrified yesterday to learn about the situation involving the threats by Steve Stephens and the tragic shooting of Mr. Godwin. Our hearts go out to his family during this time of grief. Beech Brook's offices will be closed today out of concerns for the safety of our staff, clients and other visitors to our sites. This includes the administrative headquarters at 3737 Lander Road in Pepper Pike and our Family Drop-In Center, located on the second floor of the Carl B. Stokes Social Services Building at 6001 Woodland Ave. A decision will be made later today about the re-opening of the buildings. Mr. Stephens has been a Beech Brook employee since 2008. He has been working as a vocational specialist for our Assertive Community Treatment (ACT) team for youth and young adults. since April of 2015. Prior to that, he had worked as a youth mentor."
In the Facebook video, Stephen claims to have committed 13-14 homicides. However, police said they have no evidence to support that after checking several locations.
"There are no more victims tied to Steve and this incident," Williams said.
Facebook said the video was posted after the killing but wasn't broadcast on Facebook Live as police initially indicated. The suspect did go live on the social media site at another point Sunday.
"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."
The video was later removed by Facebook, but it was still being widely shared online early Monday.
WATCH: CRIMES ON SOCIAL MEDIA
Video of the Cleveland murder is not the first crime posted on Facebook.
In Chicago, a special needs man was tortured, another teenager was sexually assaulted and a pregnant woman and child were murdered --- all broadcast on Facebook Live.
In Cleveland, the police chief said the incident is "traumatizing to our community, to everybody."
"He wanted this to be public, that was the function, that was the goal. It's not like he accidently taped the crime," said Bree McEwan, a DePaul professor who wrote "Navigating New Media Networks.
McEwan said social media users are subjected to disturbing images they might not want to see.
"They sort of drag you in, in a way that you might not want to be dragged in and sort of giving themselves a big stage to this terrible, horrific thing they're doing," McEwan said.
Facebook's founder Mark Zuckerberg refers to the company as a tech company, and not a media company which could be subject to Federal Communications Commission regulations in the same way that broadcast television stations are and prevent them from showing video gruesome videos such as Stephen's murder video.
Ryan Godwin, who said he is a grandson of Godwin's, had asked people to stop sharing it.
"Please, please, please stop retweeting that video and report anyone who has posted it! That is my grandfather show some respect," Ryan Godwin wrote on Twitter Sunday afternoon.
VICTIM WAS GRANDFATHER WALKING HOME FROM EASTER MEAL
Godwin was walking home from an Easter meal with his family when he was shot at about 2 p.m. EST Sunday in the 600-block of East 93rd in Cleveland's Glenville neighborhood.
His friends and family are trying to make sense of the senseless death.
"This man right here was a good man. I hate he's gone ... I don't know what I'm going to do. ... It's not real," Robert Godwin Jr. told WOIO.
Godwin Jr. told Cleveland.com that he couldn't bring himself to watch the video but learned about it from others.
"I don't really want to see it," he said.
He told the Cleveland Plain Dealer his father was a retired foundry worker who had nine children and 14 grandchildren. He enjoyed fishing and often was seen walking around with a plastic bag in his hand as he collected aluminum cans he saw on the ground.
Godwin had a shopping bag in his hand when he was shot
"He hugged my wife and me and said 'I'll see you guys next time,'" Godwin Jr. recounted. "I said 'OK, enjoy your Easter.'"
While the manhunt goes on, Godwin's family is just starting the grieving process.
"It's not real. (My father) was a good guy. He would give you the shirt off his back," Godwin Jr. said. "I hate he's gone. You know what I mean? I don't know what I'm gonna do. It's not real."
A woman hugging Godwin said, "Feels like my heart is gonna stop."
Cleveland's police chief also said several unofficial GoFundMe accounts have been set up for Godwin's family, but relatives said not to donate to them at this time because some are fake. The family plans to issue a statement about donations later.
The CNNWire and Associated Press contributed to this report.