The incident happened at 3:30 p.m. Wednesday along the 1100 block of Walnut Street.
The 65-year-old victim, who doesn't want to be identified, tells Action News he had eaten lunch at Cosi and then went next door to Caribou to buy gift cards for colleagues at his West Philadelphia church.
He then went to the corner to wait for the SEPTA route 42 bus.
That's when he tells police a man approached him and sprayed him in the face with some kind of chemical. The suspect then reached into the priest's pocket and ripped out a money clip holding cash, tearing the victim's pants.
The suspect made off with $125, fleeing eastbound on Walnut Street. He is described as a black male, mid to late 30's, 5'9" to 6', with a dark bushy mustache, wearing dark clothing.
After being alerted by a passerby, employees from the nearby Beasley firm ran to help the victim.
"You could see from the mace he was crying, tears were running down his face; his pants were ripped where they took his money clip," attorney Frances Alexander said.
A witness followed the suspect as he fled west on Walnut Street.
Three blocks away he descended the stairs to the subway at City Hall.
That's where a Septa surveillance camera caught the image as the suspect headed for the Broad Street Line.
Police are now combing through more video hoping to learn where he got off the train.
The assault has shaken people in what is considered a busy and safe section of town.
But the police say this is a rare, isolated incident.
"Center City is very safe with the sheer amount of people. The odds of being a victim of a crime are miniscule," Lt. Patrick Doherty of the Philadelphia Police Department said.
The priest, who lives in Doylestown, was taken to Thomas Jefferson University Hospital, where he was treated and later released. He says it was only to monitor his high blood pressure and he's okay now.
If you know the suspect or where he is, you are asked to contact police. To submit a tip by telephone, dial 215-686-TIPS (8477) or text a tip to PPD TIP or 773847.