In a telephone interview, Shoup said he was welcoming his crews back to his supply yard around 6 p.m. Thursday, and preparing to leave, when he heard the grating sound of metal on metal.
Going down to the end of his company's driveway he saw a white car that apparently had been sideswiped, and the back of a gray car speeding away from the scene before it went under a railroad trestle and disappeared.
"It's a blind hill. There are lots of accidents, probably four or five ever year. Initially we thought it was just someone going too fast," he said.
A side air bag had deployed on the white vehicle and an ambulance crew arrived to treat its male driver, who appeared to be shaken up but not badly injured, said Shoup who watched from about 30 feet away.
"Then there was a volley of gunfire . . . 10 to 15 shots," Shoup said, appearing to come from the area near the trestle.
"Cops were rushing down under the trestle, at least three, maybe more marked police units," Shoup said.
The ambulance workers had continued working on the man in the white car for a minute or two even after the shots, said Shoup, but then suddenly they "freaked out . . . abandoned the guy . . . started throwing all their gear into the ambulance . . . and went peeling off" in the direction of the gunfire.
"More and more police cars started swarming in. It just became like a beehive, everything started buzzing," as units from White Marsh, Plymouth Township and Lower Merion streamed in. "A helicopter was circling."
Thinking it better to head for his home in Chestnut Hill before all the roads were closed, Shoup left.
He pulled into Pacific Pride, a commercial filling station, and encountered men who appeared to be plainclothes officers. He asked what had happened and they told him a police officer had been shot.
"On my way home I saw many departments, including Cheltenham police with full lights and sirens going up Ridge Pike," he said. "It was amazing . . . pulling from that far away. That's when I knew it was pretty serious."
He arrived back at work about 6:45 this morning and expected to find the area locked down as a crime scene.
Instead, he said, "there was nothing whatsoever."
Investigators, instead, were some distance away, still searching for evidence along the SEPTA commuter rail line tracks at the end of Ernest Station Road, close to the Schuylkill River Trail.