"We are hoping that the Cleveland Police will be able to apprehend Mr. Stephens as soon as possible and before anyone else is injured".
Local, state and federal law enforcement are involved in the search, said Anthony.
The man also claimed to have committed multiple other homicides. Police say they have not verified any other shootings or deaths.
This story has been corrected to show that Facebook now says the killing was recorded and uploaded to Facebook, not broadcast live.
A spokeswoman for the behavior health facility where the suspect in the shooting of an elderly Cleveland man worked says the man underwent an extensive Federal Bureau of Investigation background check before being hired in 2008.
Nancy Kortemeyer, vice president of marketing and PR at Beech Brook, "We are doing everything we can to help and help locate him".
A $50,000 reward is now being offered for information leading to the arrest of Stephens, Cleveland authorities announced at a news conference Monday afternoon.
It was not immediately known what Stephens does for the agency, which said it will serve more than 18,000 children and families this year, according to its website.
In a statement, the spokesperson said the shooting was a "horrific crime".
A spokeswoman for Beech Brook, in suburban Pepper Pike, issued a statement Monday that says 37-year-old suspect Steve Stephens has been employed there since 2008 and has been a vocational specialist in a program for youth and young adults since 2015.
They had no comment on the search in Philadelphia, other than to say every lead is being followed to find Stephens.
Officials told the public to dial 911 or 1 (800) Call-FBI with any information. Then in March, a 15-year-old Chicago girl was apparently sexually assaulted by five or six men or boys on Facebook Live, and none of the roughly 40 people who watched the live video reported the attack to police, authorities said. He tells Godwin a woman's name, claiming "she's the reason that this is about to happen to you" - Godwin doesn't appear to recognise the name.
Williams also asked for Stephens to turn himself in.
Police said Sunday night Stephens may have now left the state and they are warning residents of Pennsylvania, Indiana, Michigan and NY to be on alert.
"He is considered armed and risky, so we want people to be careful out there", Williams said.
Police have been searching for the suspect since early Sunday evening, and he is believed to be driving a white Ford Fusion bearing the temporary tag of E36363.
A manhunt is on for Steve Stephens, the Cleveland man who allegedly posted to Facebook video of the killing of 74-year-old Robert Goodwin Sr.
The video of the killing was up for about three hours before it was removed. They spoke the next day, she said, and he told her he was shooting people because he was angry with his girlfriend.