No because they have too many things in common
For the US; just Kennedy in '63.
No US president- elect has been assassinated. Four sitting presidents have been assassinated: Lincoln.Garfield,McKinley and Kennedy.
The US has no crown jewels that relate to the president. Undoubtedly some of the presidents or their wives owned jewelry.
John F Kennedy was assassinated by getting shot by a gun.
None of the four assassinations of US Presidents occurred in the White House.
No. He was, however, one of the only two US presidents to be impeached (the other is Clinton).
Theodore Roosevelt was a former US President and a candidate for that office when he was shot and wounded.
No former US president was ever assassinated. Theodore Roosevelt escaped an assassination attempt while he was running for a third term in 1912. I can not think of any non-US former presidents who were assassinated.
They are dependent on wives
There have been FOUR Presidents assassinated, not three. They were Abraham Lincoln, James A. Garfield, William McKinley, and John F. Kennedy.
Abraham Lincoln--assassinated by a Confederate sympathizer James Garfield--assassinated by a disgruntled office seeker William McKinley--assassinated by an anarchist John F. Kennedy--assassinated by Lee Harvey Oswald in a still-obscure chain of events