Very simple.
Oswald took his rifle to work that day.
He did absolutely none of his assigned work.
He left his rifle, prints, shell casings, rifle bag, and fiber evidence on the boxes of the sniper's nest and the rifle.
His rifle was matched to both the bullet and shell casing evidence.
He was alone on the floor from which the shots were fired.
He was seen firing on the president.
After he escaped the building, he used his pistol to murder Officer Tippet, who pulled over to talk to him after Oswald's description was radioed to the police. Doesn't sound much like innocence to me!
He tried, but failed, to shoot the arresting officers shortly thereafter.
Evidence found in his belongings prove that he had also tried to assassinate another public figure months earlier (General Walker) but missed.
It is clear from the things he said and did and wrote, that he wanted to be famous and get his name in the history books.
So the obvious theory that best covers the available facts, are that Lee Harvey Oswald, with no sign of, or need for, outside help shot JFK.
John F Kennedy was assassinated by Lee Harvey Oswald.
John F Kennedy was assassinated by Lee Harvey Oswald.
Lee Harvey Oswald
No, Lee Harvey Oswald assassinated John F. Kennedy. James Earl Ray assassinated Martin Luther King Jr.
Lee Harvey Oswald killed John F. Kennedy.
John F. Kennedy
John F. Kennedy
Lee Harvey Oswald.
Lee Harvey Oswald
Lee Harvey Oswald assassinated President Kennedy in Dallas, Texas.
John F. Kennedy was assassinated on November 22, 1963. He was killed by Lee Harvey Oswald.
John (President) was assassinated in 1963 by Lee Harvey Oswald, and his brother Robert was killed in 1968 by Sirhan Sirhan.