While prosecuting Shaygan, the U.S. attorney's office began a secret, undisclosed side investigation of Shaygan's legal team, citing a suspicion of witness tampering on the part of the defense.

No evidence surfaced that the defense team was manipulating witnesses. On the contrary, defense attorneys rejected bribery invitations floated on tape from government informants.

Prosecutors used their trial witnesses -- informants in the criminal case -- to tape the defense team. The lawyers did nothing wrong. But the prosecutors not only didn't disclose the illegal scheme, they called the witnesses at trial and didn't mention it.

The government falsely introduced those informants -- former patients of the doctor -- as impartial, neutral witnesses.

Jurors, and the judge presiding over the case, found out about the tape recordings by accident, when one of the informants blurted out their existence while testifying.

In addition to fining the U.S. $600,000:

[Judge] Gold formally reprimanded prosecutors Sean Cronin, Karen Gilbert and Andrea Hoffman and said he would send a copy of the order to the Florida Bar for its review.

The U.S. Attorney for Miami issued a statement:

''Our Office policy, which requires the prior approval of senior management before this type of witness tampering investigation is commenced, exists to prevent precisely this type of situation,'' spokeswoman Alicia Valle wrote. ``We regret that the policy was not followed, have already apologized to counsel, and have taken steps to ensure that this will not happen again.''