Missing on the last Halloween of the 1960s: Patricia Spencer and Pamela Sue Hobley respectively 16 and 15 years old; they vanished from Oscoda, Michigan, on October 31, 1969. (Links are to Charley Project descriptions, details of disappearance, and photos.) Haven't found much on the two - the Oscoda newspaper evidently ran an article in July, but it may not be online. While Topix is not something I'd ordinarily link to or recommend, the "Pamela Hobley & Patricia Spencer Missing since October 1969" page seems actually very informative, and civil. The last entry was in July '11. That page - 17 comments right now - is here. CarlK90245 has links to the girls's NamUs pages (posted in relation to a UID in Florida, 1973), second entry here. Interesting case. I'd never heard of it.