The mystery that has transfixed the Philadelphia area over the past week — the disappearance of four young men — took a grisly turn when human remains were discovered in a 12½-foot-deep grave on a farm. The four men, all residents of Bucks County, disappeared last week. At least three knew each other. The remains of only one, 19-year-old Dean Finocchiaro, have been identified, though authorities said other remains were found in the hole as well.