Eventually Sly got a 10-year ban but was reinstated after 8, probably because he found a way to cheat time somehow.
Boris and His Magical Blade
In 1976, the Soviets and the west were in a race to see who could perfect cheating technology first. During the 1976 Olympic games pentathlon, it became clear who had the edge.
After the first event the Soviets found themselves in fourth place, right behind the British. During the next event, fencing, Boris Onishchenko made quick work of his first British opponent. Boris was considered the best fencer in the competition, so that wouldn't have raised all that many British eyebrows.
What did raise suspicions was when, during his match, the British captain Jim Fox leaned all the way back and saw Boris' sword come up a foot short, and yet the buzzer still sounded and the point was awarded. This is basically the equivalent of Shaq stepping up for a free throw, tossing up an air ball and still getting the point.
At this point the British squad called shenanigans and the sword was confiscated. In those events, there is an electronic sensor in the sword that determines when a point had been struck.
It turned out Boris had tampered with the circuit system, allowing him to award himself points at will.
Did it work?
After he was caught, the entire pentathlon team was disqualified and the British won the gold.
As if being caught performing a fairly obvious attempt at cheating, the story still manages to get more embarrassing as, after the confiscation of the sword, the bout continued and Boris ran away as a convincing winner. So the Soviets were from the New England Patriots school of cheating, which says that even if you're vastly superior to your opponent, you cheat anyway. Just for the pure hell of it.