There are actually many criminal purposes. Some people commit crimes for money, some for feelings, some for revenge, and some for impulse. A man may kill a couple because of emotional problems, or it may be because a girl has feelings for herself and then doesn't want to divorce her husband. When she came to her door, her husband was with the girl. In the case of quarrel, I remembered the motive of killing, probably because of money. On the way, I was embarrassed by my wallet and suddenly thought of robbing others to satisfy my money desire, so I met this couple. When a man and a man were arguing, it suddenly occurred to me to kill for money. It is also possible that because the man's heart is full of negative energy, he began to have the idea of revenge on the society and happened to meet this couple, so the couple became a substitute for his venting.
In short, there are many motives. Personally, I think that thinking about killing people is an extreme practice. No matter what kind of mental state he has, his behavior should be punished and severely cracked down. In the end, his motive for killing the couple was that we didn't know what caused him to have such an idea until he was brought to justice. He used cruel means to end other people's lives to satisfy his momentary pleasure. The French open is long and loose, and one day the truth will surface.