I have a theory that the secretary was the one who killed Jungman's wife, maybe he f**ked around with the breaks causing the accident. He's intending to kill both the wife and Jihyun as well since JY said he too was in the car, but he survived. He's loyal to Jungman so JM would trust him. So now he was hoping to be the heir once Jungman disown his son. But all that went out of the window since Yisu came in.
I have a theory that the secretary was the one who killed Jungman's wife, maybe he f**ked around with the breaks causing the accident. He's intending to kill both the wife and Jihyun as well since JY said he too was in the car, but he survived. He's loyal to Jungman so JM would trust him. So now he was hoping to be the heir once Jungman disown his son. But all that went out of the window since Yisu came in.