I can’t find much about this missing family online but I’ve been searching for years; maybe someone else will have better luck. The article is available in google archives but the print is smeared so I’ve provided a clearer copy.
Since the article’s publication David Dennison’s mother and father have passed away—he’s listed in both obituaries as a surviving son residing in Zaragoza. Oddly, Sylvia Dennison’s obit lists his wife as “Marylin” which is slightly different than the Pittsburg Post Gazette’s “Marialin,” but the discrepancy may simply be a typo.
I rarely don my tinfoil hat but I’m pretty sure the answer to this mystery can be summed up in three little letters: C(entral) I(ntelligence) A(gency). I’d love to know more, however—Mary Dolores, if you’re out there, ayúdame por favor!