The 36-year-old Olson was accused of defrauding septic customers. He pleaded guilty to second-degree theft.
The judge on Friday put Olson on probation until he pays a still-to-be-determined amount of restitution. She also suspended imposition of sentence. That means his conviction can be set aside if he completes his probation.
The Fairbanks Daily News-Miner says Olson's help led to the arrest of Schaeffer Cox and four people associated with Cox's Peacemakers Militia.
Prosecutors say the group made plans to kill Alaska state troopers, judges and court officials. All have pleaded not guilty to charges in the case.
