Please call the worker to find out the reason behind their long tenure and whether this is their first instance of such behavior. If the worker acknowledges their mistake, apologizes, and corrects it, that is acceptable. If not, issue a charge sheet, conduct an inquiry, and take action in accordance with the certified standing orders/model standing orders.
Initially, attempt to resolve the issue amicably as errors are inevitable and could have arisen due to differences in opinions.
Regards,
Kamesh