He said he was heartened that the suspected killer was captured, "and I expect him to be brought to justice," Nutter said. "But this is the reality that takes place on the streets of Philadelphia."
Philadelphia Fire Commissioner Lloyd Ayers said the death of Cassidy would serve as a "rallying call" to deal with violence in the city.
"We understand the meaning of working together, mourning together," Ayers said. "That's the message I took from today. We can do this. Coming together, we have an opportunity now."