The search for a suspect who police believe randomly shot a man walking along a Cleveland-area sidewalk on Sunday before posting a video of the fatal shooting on Facebook broadened nationwide today as officials acknowledged that they did not know where the man was and announced a $50,000 reward for information leading to his arrest.

Police in Philadelphia said that they had received multiple reports of unconfirmed sightings of the wanted man, Steve Stephens, at the Belmont Plateau park area in the western part of the city. In a statement this afternoon, however, they said that so far, there was “no indication” that the suspect had actually been there, though they had locked down nearby schools as a precaution.

Chief Calvin D. Williams of the Cleveland Police Department said today that authorities had searched “every location” where Stephens has resided, as well as places where his family members live. They have recovered items, including weapons, and “other things that are pertinent to the investigation,” he said, without specifying to whom those items belonged.

“I think we can say without a doubt, he’s armed,” Williams said. “Steve, if you’re out there listening, call someone.”

Stephens, 37, is being sought in what authorities said was a random shooting of Robert Godwin Sr., 74.

A warrant for Stephens’ arrest on a charge of aggravated murder has been issued, and police asked residents of Indiana, Michigan, New York, northeast Ohio and Pennsylvania to be on alert. Stephens said in a video on Sunday that he had killed multiple people, but police said there was only one known victim.

At an earlier news conference, Williams said detectives had talked to Stephens on the phone, but he did not elaborate. Stephens had many motor vehicle violations but no criminal record, he said.

In the minute-long shooting video, a driver pulls up to an older man on a sidewalk. The driver asks the man to say a person’s name, then pulls out a gun and shoots him.

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