"There is no doubt in the witness' mind - no doubt at all - that he knew what he did," Adams said.
The driver is believed to be a light-colored black or Hispanic man with a closely cut full beard and short curly hair, about 6 feet 2 inches, with a stocky build and possibly wearing a red jacket.
The vehicle of interest is an early 2000s model light-colored Chevy Suburban, possibly light tan or gray, with rectangular-shaped headlights. This vehicle may have damage to the orange plastic light assembly.
Adams said his investigators have received a few tips, but nothing solid. A surveillance camera outside a home captured footage of the suspected SUV.
"That video is pretty clear," Adams said.
McCaughan lived nearby. He had moved in with his brother, Christopher, who is in remission from testicular and skin cancer, according to the Delaware County Daily Times.
"He came here to take care of me," Christopher McCaughan told the newspaper. "I've got to take a shot once a week, he gives me my shot. Now, I've got to find somebody else to give me my shot. I can't take needles. I can't do it. I'm scared of them."
McCaughan died less than a mile away from the scene of another fatal hit-and-run in Upper Darby in January. The driver in that case, Ernest Marks, came forward and admitted to killing Richard Patterson, 69, and his 5-year-old poodle, after seeing news accounts of the accident.
Tipsters may contact Collingdale Police at 610-586-0502 or the Delaware County Communication Center at 610-565-6500.
On Twitter: @wbender99