I should press charges and contact your insurance company. If it was just a wiped drive, your insurance company may cover data recovery services. They should also be advised due to this being a data breach. You may also want to contact your attorney for additional advice on how to proceed with both the former employee and the data that they potentially stole. Until you have the drive analyzed, you don’t know if it’s a replacement. They may have kept a copy of the data before wiping the drive or if they swapped out the drive for a new one. In the case of the latter, they very well may have retained the drive.
Communication is incredibly important in business. Speak to them and encouragingly explain to them how they can do better.