A person X is a network administrator for the ABC Company

A person X is a network administrator for the ABC Company. A person is passed over for promotion three times. He is quite vocal in his dissatisfaction with this situation. In fact, he begins to express negative opinions about the organization in general. Eventually, X quits and begins his own consulting business. Six months after X’s departure, it is discovered that a good deal of the ABC Company’s research has suddenly been duplicated by a competitor. Executives at ABC suspect that X has done some consulting work for this competitor and may have passed on sensitive data. However, in the interim since X left, his computer has been formatted and assigned to another person. ABC has no evidence that X did anything wrong. What steps might have been taken to detect X’s alleged industrial espionage? What steps might have been taken to prevent his perpetrating such an offense?