crime and punishment has always been
- subject and linking verb
While others think that all of the crimes have to be investigated exactly as well as circumstances and motivation should be considered for judging and punishing them fairly.
break this sentence into two
take two murderers for an example who has killed someone
naturally murderers killed someone that is why they are called as such
In conclusion,crime and punishment have always existed and the main thing is not to punish but to penalize fairly.
besides that it is short, I think it does not relate much to the ideas you have presented in your body paragraphs.
To give you more essay structure ideas I will be using this prompt on my next work