Props to theatresphynx and woap, who correctly figured that (A)pulling three socks would guarantee a matching set, and (B) the man was dressed as a sailor. While there could be an argument that there are no mile and a half sidewalks in NYC, once you get into the outlying areas, that may not be a problem. The correct answer, was that there are no cement sidewalks in NYC, or anywhere else; they're made of concrete, of which cement is only one ingredient.
Well, let's get back on track, shall we?
Neon Slick adjusted his sunglasses as he sped down the winding mountain road into town. Being very near-sighted, he required corrective lenses. Arriving at the optician's, he tried on his new lenses, and since he could now see perfectly, decided to wear them home. On his way back, Neon saw his brother-in-law, Sid Shady*. He stopped and a violent argument ensued. Sid picked up a rock and smashed it on Neon's forehead, killing him. Sid then put the dead body into the car. Seeing Neon's sunglasses on the passenger seat, he slipped them on Neon and then pushed the car off the road, down a steep ravine. When Detective Shadow examined the body, he declared that it was no accident, but a heinous murder. Why was Shadow convinced that Neon was murdered?
*Note: As soon as you saw this name, you knew it was a murder problem, didn't ya? No, Neon's being related by marriage to Sid Shady is not enough evidence for Shadow to declare it a murder. ;)