If there is enough proof to grant them access to these records, why isn't a prosecutor taking over the case ? Giving access to confidential data to the adversarial party doesn't seem very wise.
Also, setting the bar that high for discovery wouldn't make any sense. To initiate an arrest and criminal prosecution, you essentially have to have a "more likely than not he did it" belief in the suspect's guilt. But the "more likely than not" standard is all it takes to win a civil case. So by the time you get enough evidence to initiate a criminal case, you have enough to win a civil case.
Most of these are civil cases; Chevron is the plaintiff in some and the defendant in others.