A rental car company is under investigation after charges that the firm was illegally charging renters $100 per rental, with a standard one-time fee.

Nike is being investigated by the Orange County Sheriff’s Office, according to an Orange County Register report.

The investigation began last month when a former employee filed a complaint against the firm, saying that she had been falsely billed for rental cars and cars with no actual cars on the lot, and that the company failed to keep proper records of all the rental cars.

The deputy who investigated the matter has been transferred to another agency, according the report.

The deputy is not believed to have received a formal complaint.

In a statement to the Register, a Nike spokesperson said the company is cooperating fully with the investigation.