Was the Kennedy assassination a conspiracy?

There is no possible or reasonable explanation that could persuade me to believe that John F. Kennedy's assassination was a conspiracy formed by the CIA, FBI, or any organized crime. First of all, after forty-four years of investigation by countless researchers, not one piece of credible evidence was found to support this theory. Sure, these groups had a motive: Members of the anti-Castro cause were infuriated by JFK's betraying the anti-Castro clause; however, there is no evidence to support that they did, in fact, assassinate him. Moreover, there are over fifty-three found pieces of evidence that irresistibly point to Lee Harvey Oswald and his guilt. His weapon was his own $12 mail-order rifle, hardly the equipment used by an expert shot. He was the only employee who fled the Texas School Book Depository after the shooting, killing a Dallas police officer forty-five minutes later and then, thirty minutes after that, he resisted arresting and pulled his gun on the arresting officer. If he were the shooter for the conspirators, wouldn't they have had a car waiting for him to bring him to a secluded hide-out or, more likely, bring him to his death? His defense was merely a string of provable lies, which all pointed to his guilt. How is anyone supposed to believe that fifty-three pieces of evidence that lead to this guilt could possibly make Oswald innocent? He was an unreliable, emotionally unstable misfit who had previously tried to commit suicide after the Soviets rejected his hopes of citizenship. How is anyone to believe in this conspiracy theory considering Oswald’s state of mind, lack of expert shooting skills and the fact that after forty-three years not one word of this alleged conspiracy leaked out? Surely no rational person can believe this, when the evidence against this theory is overwhelming to the dismal evidence, or lack thereof, that point to there being a conspiracy.