Crouch and Judge Kristin Ruth were indicted by a grand jury in June for their alleged handling of dozens of DWI cases.
As ABC11 first reported in February, the senior resident Superior Court judge in Wake County - Judge Donald Stephens - asked the SBI to look into the matter after he was alerted to the issue in a letter from Wake County District Attorney Colon Willoughby.
In his letter, Willoughby said he found "a disturbing pattern of what may be unauthorized and illegal judgments."
The DA said in at least a dozen cases, a person was convicted of DWI in District Court and then the case was appealed to Superior Court. After a period of time, the appeals were withdrawn, and the cases were sent back to District Court for resentencing.
In all 12 cases, Willoughby said Judge Ruth - who was not involved in either the original sentencing or the resentencing - entered what appear to be orders that change the effective date of the sentencing without notifying prosecutors.
Willoughby said the orders effectively backdated the convictions and shortened or eliminated the mandatory suspensions of the defendant's driver's licenses.
"In at least three of these cases, it appears that Judge Ruth has issued limited driving privileges for defendant without legal authority to do so," Willoughby wrote.
Ruth pleaded guilty in July to a misdemeanor charge of failing to discharge the duties of her office. During her pleading, she also agreed to cooperate with prosecutors in the Crouch case.
Ruth admitted that she improperly signed dozens of orders without reading them and did not know that orders allowing DWI defendants to avoid license suspensions had her signature on them.
"I signed them and did not read them because I trusted James Crouch," Ruth said.
Crouch pleaded guilty Tuesday to two felony counts of obstruction of justice, one felony count of conspiracy, and one felony count of altering documents. He could face a maximum of 13 years in prison at a sentencing hearing next month.
Crouch has lost his license to practice law.
During Tuesday's hearing, prosecutors said they had new evidence that Crouch took money from the trust fund he had set up for clients.