If his #3 was involved in all this, the chance of his knowing nothing

is just about zero.  People probably are going to jail for this, and the lawsuits and retrials are going to cost the taxpayers a fortune.  
Unlike many alleged felons in Los Angeles County, the Diana Teran scandal has the potential to topple the county's power structure, or to put a severe dent in it.

That potential exists because of the sheer volume of personnel and criminal cases Teran was involved with that might now be challenged in court, and because her actions at issue in the criminal case allegedly involve coordination with high-ranking county officials, such as Inspector General Max Huntsman, District Attorney George Gascón, and current and former members of the county Board of Supervisors.
People are going to demand their case be retried, fired officers are going to demand to be cleared and receive damages, and a bunch of corrupt politicians are going to be willing to do just about anything to stay out of jail.

Well, the voters elected the bastard and his minions, so.