Giving capital punishment has been a controversy for years. Some people believe that this kind of punishment is essential to apply because they believe criminals tend to repeat their crime as they live for it. However, some others believe that imprison criminals for quit long time will be better as it is more humane. At the same time, this punishment can make criminals get intimidated. Then, it can prevent them for repeating the same mistakes.
Even your prompt is open for discussion, there is no harm you stating your own opinion in the introduction itself. It is nicer when you conclude the intro with a statement expressing your opinion very clearly. That helps you take the reader in your desired direction. Since IELTS Task 2 is a time bound task, it is always good to follow one particular structure during practice sessions :)