It wasn't enough for O.J. Simpson that prosecutors bungled his murder case and allowed him to be free for more years than he should have ... he also called the D.A. who prosecuted him an "a**hole" ... and it's all on tape.
We've obtained footage of Simpson, shot 5 years ago for a documentary -- which shows O.J. driving through Brentwood -- the L.A. area where he slaughtered Ron Goldman and Nicole Brown Simpson back in 1994.
In one of the clips, O.J. points out the home of former District Attorney Gil Garcetti and screams, "A**hole!"
In the documentary, titled "O.J. Monster or Myth?” -- Simpson also bragged that he has hidden assets from Fred Goldman.