I agree with Mr. Sharma. Of course, it is within the domain of the Finance Department of an organization to point out financial irregularities, but they are not empowered to suggest termination of the employee concerned. The most they can suggest is the recovery of the amount, apart from disciplinary action in this regard.
The post indicates the embarrassment and hesitation of the poster Vastavaamit himself. Reimbursement of expenses like hotel bills, conveyance, etc., is there only to facilitate the work/performance of the employees, irrespective of their status, and not to make out some fraudulent income. If the hotel bills are bogus, it is very serious as it questions the integrity and honesty of the concerned employee.
No matter how efficient or good the employees are, their lack of honesty and integrity will certainly ruin the organization in the long run. At least, conduct a discreet inquiry and then decide.