The issue is that so many of the officials that investigated him were corrupt. How can we be confident any of the evidence was real. He is obviously not innocent but when at least 2 of the investigators went to jail for crimes committed during this investigation it casts serious questions on the validity of the case as a whole.

The police, DEA and Secret service have vast power they can use against the populace. If those same agents are committing crimes then it taints the entire investigation and prosecution. If a cop is found to have planted drugs on past arrestees, quite often a good portion of his other cases are thrown out as well as he has corrupted everything he touched.

It likely doesn't rise to the legal doctrine of "fruit from a poisoned tree" but its in the ballpark.

For the people downvoting me for some reason:

A DEA agent involved in the investigation "was sentenced to 78 months in prison for extortion, money laundering and obstruction of justice"

A secret service agent involved in the investigation "was sentenced to 24 months in prison by U.S. District Judge Richard Seeborg in San Francisco following his earlier guilty plea to one count of money laundering."