A ziphead was a type of person referred to by Officer Foley, possibly a person who was addicted to a drug known colloquially as "zip", or a person who, like a lo-bo, had done something to their brain. It may have something to do with the term "zipperhead", which is an offensive slur against the Asians. In 2015, Foley commented to partner Reese that Hilldale was a "breeding ground for tranks, lo-bos and zipheads".