The difference in the criminal and civil case outcomes in the O J case probably related to the difference in the burdens of proof in civil and criminal cases. It was probably the same case with the same evidence presented to two different juries. However, in criminal cases the prosecution has a very heavy burden of proof...guilt beyond a reasonable doubt. That does not mean guilt beyond all doubt. The key words are REASONABLE doubt. Remember..."If the gloves don't fit...you must acquit."  Probably go down in history as one of the greatest lines in a closing argument by a defense attorney.

On the other hand the burden of proof is less in civil cases...either by a preponderance of the evidence (51%) or in some cases proving the case by clear and convincing evidence ...which is a burden somewhere between a preponderance of the evidence and beyond a reasonable doubt.