The Harvey and Lee twin/clone caper is one of the most shameful - if not THE most shameful - and embarrassing "theories" of the JFK case. To rehash for newbies that come here, here's what folks are expected to believe:
Right after WWII, some American secret agents were in Hungary and found a kid wandering the streets there. Lo and behold he looked exactly like the American born Lee Harvey Oswald, who was at the time around 7 years of age.
Somehow, these secret agents tracked down this kid's Mom and again - lo and behold - they discovered that his Mother looked exactly like the American born Oswald's Mom EXCEPT - gasp! - she never smiled and had a unibrow. Close enough.
So they bring both of these people back to the U.S. and, together with Lee and his Mom, trained them to become secret agents too. Keep in mind that this all was taking place for around 10 whole years before Kennedy was assassinated in Dallas.
The proof of all of this happening, as explained ad naseum by true believers of the caper, was that Harvey the European boy and Lee the American one, were seen at various schools, in the military and around various towns living parallel lives. For example, Lee was going to school in LA while Harvey was going to school in NYC. And so on and so forth...
Meanwhile, the secret agents were keeping both versions of the boys and their Moms on the back burner for 10 whole years. For what nefarious reason only the secret agents and the god your choice only know.
Then on Nov 22, 1963, the hatch was sprung - one twin did the shooting of Kennedy while the other took the fall for the crime. He was picked up at the theater and was gunned down in the police station, while the other led the first one to the theater, went out the back door of the movie house and was never heard from again.
THAT is what folks are expected to believe what happened to JFK in '63. It's truly a frightening story not because it's false, but because many, many folks out there - you know the folks you walk past and see in stores and coffee shops - are the same people who actually have fallen for this story and get raving mad at you when you tell them the story is a load of bullspombleprofglidnoctobuns.