O.J. Simpson's FBI file just got released -- and right off the bat, what stands out is the fact agents went to excruciating lengths to study the shoeprint found at the murder scene.
The feds dumped their records on the late O.J. Friday -- and there's dozens of documents within it ... most of which pertain to the infamous 1994 murder of his ex-wife, Nicole Brown Simpson ... for which O.J. was the prime suspect and put on trial, only to be acquitted.