As America's TV Mom, June Cleaver was the personification of the Light in the TV Universe, of all that was good and wholesome in the American Family back in the 1950's.
But there was a dark side to her side of the family, and it all traced back to June's aunt, Martha Bronson.
Aunt Martha, according to Ward Cleaver in the "Leave It To Beaver" episode "The Visiting Aunts", lived alone in Riverside and her only family was June and her two sons, Wally and Theodore.
But Toobworld Central - yeah, just me - has a theory of relateeveety, in which Aunt Martha had an illegitimate daughter* named Jean Arnold, who would grow up to be the identical cousin of June Cleaver. Jean and June....
If Aunt Martha raised the girl, she eventually denied her relationship to her own daughter by late 1954. So that by 1958, as far as Ward and June were concerned, Aunt Martha had no other family, just as she wanted it.
Jean Arnold was a bad seed, there's no other way to put it. She had an artistic side, and gained some international fame as a ballerina. But it wasn't enough. With her partners Henri Felix and Frankie Ludwig, Jean participated in a jewel heist of uncut rubies in Hong Kong. The trio then sailed back to America, smuggling the rubies into Long Beach, California.
Jean tried to play up to Michael Lanyard, the adventurer who was known as "The Lone Wolf", but he remained suspicious of her, as did a spry old private eye named George Bracken.
(Coincidentally - par for the course in Toobworld - George had a twin brother named Gus. Gus Bracken worked as a fireman in Mayfield - where Jean Arnold's identical cousin June Cleaver lived with her family.)
In order to keep the rubies to herself, Jean murdered her partner Henri Felix and tried to charter a boat out of Long Beach to take her to San Diego. But Lanyard and her other pursuers finally caught up to her in the US Customs warehouse.
It's quite pozz'ble that June Cleaver's identical cousin eventually went to the gas chamber.
And that's why nobody in the family would ever mention Cousin Jean again, out of shame......
* It could be that Aunt Martha was married to the girl's father, a man whose surname was Arnold. But she may have divorced him and taken back her maiden name.