More than 2,000 people crammed into the basilica and its chapel for the Funeral Mass, with another thousand watching the service on a giant video screen outside.
Before the service began, family photos of Cassidy flashed on the big screen. Officers and passersby paused and watched as a slide show took everyone inside his world.
There were photos of a trip to Walt Disney World; Cassidy walking down the aisle with his bride, Judy; the family at Christmas; a daughter's graduation; a group shot of a softball team.
Several police said what made this funeral harder to take than others was the way Cassidy was killed. The shooting was captured on surveillance tape, and video clips were played over and over again on television leaving people with a vivid, disturbing feeling of being a witness to murder.
"He was ambushed," said Jerry McLaughlin, a retired Philadelphia officer who knew Cassidy and attended yesterday's funeral with his 3-year-old daughter. "He was the third cop shot in a week. Just the way it happened - he didn't have a chance."
Skip Kane, a retired Philadelphia detective, said, "This seems a lot more cold-blooded."
Joseph O'Brien, a retired captain who worked with Cassidy, said the rising violence in the city was adding to people's anguish.
"When they see a police officer shot like that, it reminds them of how vulnerable they are," O'Brien said.
People started lining up for a public viewing before the basilica opened its doors at 7:30 a.m. Many did not have a direct connection to Cassidy, but felt compelled to pay their respect.
Cecilia Hodge has an uncle who is a police officer in Florida, and said the death of any officer hits close to home. She took a morning break from her job with a securities firm to attend the viewing.
