There is no doubt that many people are in danger due to the presence of crime and violence. Although some people believe that capital punishments are necessary, in my opinion, those kinds of punishments are not as important a solution for crime as they think.
First and foremost, it is important to acknowledge that some innocent people can be convicted to death. This is a problem for both the people who will be punished and their families because those punishments usually cause irreversible harm to those people. Although the government may prove their innocence after their punishments and then try to compensate for the damage, they cannot bring dead people back. If they had not been sentenced to death, they would have been free. To make matters worse, if these innocent people are punished to death, the evidence they have may be destroyed at the same time, and proving their innocence cannot be possible because of that. For example, in the US, a man proved that he was not guilty after 25 years in prison. Consequently, killing people as a punishment may lead to a deterioration in society and decrease public belief in their legal system.
That said, capital punishments are incapable of preventing crime. This is because people who commit crimes have psychological disorders, such as a tendency to harass. This may be the reason why capital punishments are not able to discourage criminals from bad actions. Furthermore, the crime rates of countries that have capital punishment in their legal systems are higher than those of other countries. It may indicate that a conviction for death is an ineffective method to protect civilians from malicious attacks.
In conclusion, it is impossible to think that people can be preserved from crime if countries sentence criminals to death. I believe that while capital punishments may not contribute to a to a decreasing crime rate, educating people can be a much effective way than enforcing those punishments.