
PHILADELPHIA (WPVI) -- Police are searching for a masked suspect whom investigators say has been terrorizing people in Center City Philadelphia.
Video released by police Monday shows a masked man chasing a woman who was jogging near City Hall last Wednesday around 5:30 a.m.
"He was holding his cellphone in front of her, at which point he asked her, 'Are you ready to die?'" Philadelphia Police Capt. Jason Smith said.

Police said the startled victim attempted to flee.
"The female is screaming for help this entire time," Smith said. The "male abruptly stops and heads northbound on 15th Street, at which point he gets on the escalators at Suburban Station."
Another woman recalled her encounter with the suspect minutes before.
Jameka, who asked not to use her last name, said she spotted the masked suspect approaching the runner near the La Colombe coffee shop. She said the woman was wearing headphones.
"I started to wave at her from across the intersection and say, 'Hey there's someone behind you, look behind you.' And she heard me, and then she started to run away," Jameka recalled.
She then witnessed him try to force his way into La Colombe before turning his attention towards her.
"I figured if anything was going to happen, I wanted to see it with my own two eyes," she said.
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She turned around, screamed and kicked the attacker in the chest.
But she said something seemed off about the man.
"He just seemed so disoriented about what his goals actually were. I had bags; he wasn't reaching for those. It didn't seem like he had a clear goal to like actually get in La Colombe to do anything, so I was like OK, well, let's see if you can fight, and he couldn't."
While at the coffee shop, Kate Egan told Action News that the suspect terrorized one of her coworkers, but a security guard intervened.
All of the victims were able to get away unharmed.
"It's pretty disturbing," Egan said.
The incidents have left Egan and others concerned.
"It's really unsettling just trying to get to work and have a kid like this actively terrorizing women," Egan said. "I really hope he is caught."
Investigators believe the suspect is between 16 and 20 years old.
Police said the suspect allegedly implied he had a weapon at one point, although no weapon was ever seen.
Authorities said the suspect is facing charges including terroristic threats, harassment, simple assault and intimidation.
Anyone with information is asked to contact Philadelphia police by calling 215-686-TIPS (8477).