It seems there is more to this than at first apparent. The attached clipping, from The South Florida Sun Sentinel, refers to her disappearing with a partner (Marvin Schlossberg) and blood and a spent bullet being found in their house. It seems that although they had last been seen in July 1982, their disappearance was not discovered and reported until October - when Marvin's wife (from whom he was clearly separated and living with Robin) came looking for him and made the report.
It seems that Marvin is Marvin Edward Schlossberg, born 1943 in New York and with a death date of July 1982 according to family trees on Ancestry and 1987 according to the date on the Florida Death Index (which suggests, like Robin, this is a date of declaration of death rather than a confirmed death date). The July 1982 date is also confirmed by the Social Security Claims Index.
Strangely, I can find no record of Marvin being listed as a missing person despite the death records. I attach a picture of Marvin from Ancestry, from an unknown date. Not only is there no missing report on Marvin, but his entire online footprint is minimal. For a man who obviously had money (nice house, going to Kentucky on equine matters) it is less than obvious what job he had or where his money came from.
It seems more digging is in order.
