Depending on the severity of fraud suspected it may be best for the company to just let them go as their punishment to quickly cut ties to prevent a large loss. If it is believed that a very large case of fraud has been committed the company will want it fully investigated to pursue future civil or criminal charges against the employee.
The victim's anger can ruin the investigation if they confront the suspected employee too soon which could cause the suspected employee to quit before the investigator was able to obtain all the needed evidence for fraudulent charges.