Thornsbury has pleaded guilty to conspiring to deprive White of his constitutional rights and has resigned from the bench.
A recently unsealed federal search warrant shows the FBI was investigating the former sheriff on suspicion of money laundering in the weeks before he died. The document says Crum allegedly arranged to buy campaign signs with cash obtained from a doctor convicted of running a pill mill.
The warrant says Dr. Diane Shafer paid White hundreds of thousands of dollars in cash to for making Crum's campaign signs.
The FBI also was investigating whether Crum committed mail fraud by submitting fake campaign disclosure forms by mail, whether Crum possessed illegal drugs and whether he intended to distribute those drugs.
Federal prosecutors say Crum had White arrested instead of paying a $3,000 debt to the sign maker. White then went to federal agents and told them about providing Crum with pills.
When the alleged conspirators learned White was talking, they allegedly offered him a deal. Federal prosecutors say they told White he would get a lighter sentence if he fired his lawyer and hired one they preferred.
White was eventually sentenced to 1 to 15 years in prison on drug charges.
Shafer was sentenced to six months in jail after pleading guilty in an unrelated case to misusing her Drug Enforcement Administration registration number.