I just watched the movie 12 Palace, and I feel too documentary to understand.

This is a suspense film with some documentaries. To express what functions are different, I can only share what I know with you. I feel that the reason why it becomes an unsolved case is related to the age of the case.

In the 1960- 1970' s, a guy who called himself "the black boy of the zodiac" murdered at least five people in the coastal area of San Francisco, USA. Before and after each murder, he would write letters, mail parcels or call the media to expose criminal clues. In the letter, he drew four password numbers, just like a bad-tempered teacher, telling the police to solve this problem quickly, or I will kill someone. He is not joking at all. Among the victims were young couples, single women and strong young men. The means of killing are guns and knives, and the place of killing is around San Francisco, which seems to be disorganized.

1968 12.20 "Zodiac killer" shot the first couple, and he did it again half a year later. Later, he sent letters to three local media, claiming responsibility for two murders, and listed a 408-letter number with his name hidden. After that, Zodiac sent at least 18 letters to the media. In the second letter, he chose the "Zodiac" which refers to the twelve constellations. Some letters attached the victim's blood-stained clothes to prove his identity, some revealed his next criminal plan, and some expressed his dissatisfaction with reality. For example, a letter said: "The media should help the public pay tribute to the wonderful murder, not to the murder trial." Some people just laugh at the media and the police. In two letters to San Francisco Yearbook, he complained that there were too many advertisements and so-and-so columnist was too bad: "He can only write anonymously, and I will do it."

Murder survivors recalled the appearance of the "Zodiac": wearing a black hoodie with the executioner's face hidden in the hat, wearing sunglasses and a shiny white cross pattern on the chest. Other witnesses staged "Rashomon", and the police finally confirmed only one clue. He is a man between 35 and 45 years old. Suspects of the zodiac can also draw up a long list. Famous lawyers include a lawyer who firmly believes that his brother is a killer (he calls his brother "Zodiac Jack"), a member of the Manson family, a citizen named Kane, Ted among the Kaczynski brothers, and one named Arthur? Lee? Allen, a San Francisco resident, is recognized as the champion of the Zodiac Killer Championship. Arthur's DNA was detected in a letter of the zodiac in 2002, but he died of old age at home on 1992.