In the 1990s, Jilin dispatched police from across the city to solve a major serial murder case. The murderer was extremely arrogant. He not only killed innocent people who had conflicts with him, but also killed many police officers with cruel methods.

One day in July 1991, Chang Guoyi, a cadre working at the Jilin Procuratorate, walked home alone after get off work. At that time, the police would also be equipped with pistols. Chang Guo walked in the dark alley with a pistol on his waist. He always felt that someone was following him behind him, so he walked quickly towards the door with fast steps.

The moment Chang Guoyi opened the door, a person suddenly appeared behind him, and then with a scream, Chang Guoyi fell on the door.

Chang Guoyi’s brother was at home at the time, but at this time Chang Guoyi’s brother was so frightened by this scene that he escaped from the window. He did not dare to go home until the house was not moved. An ambulance was called, the police were called.

Unfortunately, Chang Guoyi died after being sent to the hospital that night. The cause of death was a skull fracture, with nails driven into Chang Guoyi's skull.

The police found the murder weapon at the door of Chang Guoyi, a nail gun commonly used for welding and home decoration, but this one was rebuilt after welding and was stronger. According to the footprints at the scene, two men could be identified, one of whom was 1.75 tall. .

Not only that, Chang Guoyi was robbed by two murderers with a gun on his waist. After investigation, the police believed that the two murderers were probably armed with guns.

The modified nail gun found at the scene led the police to believe that the murderer might be engaged in the construction and decoration industries. The police launched an investigation based on this clue. However, Jilin City was engaged in related industries at the time and there were a very large number of workers who met the investigation conditions, making the investigation very difficult.

After more than a month of investigation, a worker at one of the bases came to the door and admitted that he had modified a nail gun. Will the murderer be caught this way?

Wang Deyong, a workshop worker, admitted to the police that the nail gun had changed his hand. This news excited the work group staff, and then under the pressure of the police, Wang Deyong also discovered that Li Xiaodong believed that with the police, he said in the workshop Li Xiaodong thought that the nail gun made him change.

The police immediately arrested Li Xiaodong and found that Li Xiaodong's physical characteristics were very similar to the murderer. Li Xiaodong was really absent from work that day and might have the opportunity to commit a crime.

Due to the high pressure of the case, the special team hoped to solve the case as soon as possible, but they made a mistake. They quickly found out that Li Xiaodong was the murderer and Wang Deyong was the murderer. Even though Wang Deyong's testimony was full of loopholes, the two were extremely inconsistent with the facts of the case, and often reversed their confessions during the trial, the case ended like this.

Soon some of the task force officers realized their mistake. Because not long after Chang Guoyi's case, another major case occurred, which made the police realize that the real murderer was still at large. The police officer on duty at Shahezi Police Station was killed!

That night, after talking on the phone with his wife and children, a drowsy police officer rested on his office desk. Another officer took his son to the police station because no one at home was concerned about his son being home alone that day.

Suddenly, two black figures turned from the window, and the remaining police officers were killed by the gunman before they could react. Another officer heard the sound before he could resist or run away, and his son was shot dead and lay in a pool of blood. The gun used by the murderer was the one Chang Guoyi lost.

As soon as this case occurred, all the police officers handling the case were devastated and angry at the same time. The "murderer" was still locked in the police station, but tragedy happened again. It seems that the real murderer is still at large. . The murderer's crime was clever, leaving only broken fingerprints, and later removed other traces. It must have been a repetition. The task force is determined to catch them and bring them to justice.

By comparing similar cases before 1991, the police found that several nail-shooting incidents occurred as early as 1988. After combining all the clues and comparing the broken fingerprints, the police finally captured welders Zhang Xiaolin and Zou Guangqiang in a residential building.

After being arrested, the two confessed to the police that they killed 19 people between 1988 and 1992.

Both of them have served time for crimes against the law. After they came out, they were dissatisfied with society and refused to accept the punishment of the law. Therefore, they decide to take revenge on society and commit multiple crimes. However, both of them could not escape the punishment of the law and were sentenced to death, ending their evil lives.