The church ceremony drew not only thousands of Fox's brothers in blue, friends, and relatives, but also people who had never met the seven-year veteran. Fox died a day before his 35th birthday, leaving behind his wife, Lynsay, and their young daughter, Kadence.
"We wanted to pay our respects to a real hero," said Janet Roop of Plymouth Meeting. She and her husband, Jaime, rode to the church on bicycles and watched from a parking lot across the street.
"I just wanted to give her support, even if it's from a distance," she said, referring to Fox's widow and breaking into tears.
The line in front of the church formed about 5 p.m. and did not thin even when gray clouds dumped buckets of water on the mourners and the air turned cold.
Thousands of people, most of them police officers from nearly 50 agencies in Pennsylvania, New Jersey, and Delaware, braved the wind and rain for hours just so they could say goodbye to Fox, a Marine who served two tours of duty in Iraq.
Montgomery County District Attorney Risa Vetri Ferman called him an "incredible human being."
Ferman, Plymouth Township Police Chief Joseph Lawrence, and a relative of Fox's were expected to talk to the media at 5:30, but shortly before that time a county spokesman said they were not up for it.
Pat Gabel, 73, made sure she showed up to honor the fallen officer, taking a shuttle bus from a community center to the church.
She did not know Fox, she said, but she came because Plymouth police had often escorted her to the hospital when she got sick.
"I feel grateful," she said.
"It's a terrible thing," she said. "It's like reliving the Kennedy assassination, in a way. He was very brave."
She also watched the motorcade on Monday. "It was something to see," Gabel said.
Fox was shot by Andrew Charles Thomas, 44, of Lower Merion, who was driving a stolen car the wrong way past the officer on East Ridge Pike, according to the District Attorney's Office.
Fox and another officer followed Thomas, who was driving a silver Infiniti SUV. He struck another car and ran away.
Fox and his police dog, Nick, chased Thomas into an industrial area alongside the Schuylkill River Trail. At some point, according to authorities, Thomas fired four times at Fox and Nick from a hill.
Fox was struck once in the head and Nick was grazed by another bullet.
Officers responding to the scene found Thomas with two gunshot wounds. The Chester County coroner said Thomas had committed suicide.
The last police officer from the Philadelphia suburbs to die in the line of duty was Officer Christopher Jones of Middletown Township, Bucks County, who was struck and killed after a traffic stop along Route 1 in January 2009.
Another public viewing for Fox is set for 7 a.m. Wednesday at the church, to be followed by a Mass at 11. Burial is scheduled for 2:30 p.m. in Washington Crossing National Cemetery in Newtown.
Janet Roop said that thinking about Fox running after the suspect and being killed so close to her home "was horrific."
"It's sad," she said. "I'm so tired of gun violence. The answer is to get rid of them. It's dangerous, and it's scary."
Contact Kathy Boccella at 610-313-8123, firstname.lastname@example.org or @kmboccella on Twitter.