You can take the story of sherlock holmes.You can change the characters of he story.
The story involves 5 characters.
4)The dead man
5)The dead man's son
7)Dead man's friend
Once a police officer meets a detective for ask to help him in a case.The case was about a man who was killed.When the detective along with his two assistants and a police officers go to the dead man's house they see the dead man's best friend.When they investigate about the case to him, the friend of the dead man says that there was quarrel between the dead man and his son.So the dead man's friend told that the dead man's son would have killed his own father.Taking the dead man's friend as a good witness the police officer arrests the dead man's son.
Don't think that the detective has no role in the story.The detective did not believe what the dead man's friend told and further investigates the case secretly.And soon he finds that the dead man's son is not the victim and the friend of the dead man was the victim.The friend kills him because the dead man had threatened the friend of his with the money he had given.
The story ends with how the detective and his two assistants prove that the dead man's son was not the culprit and the dead man's friend was the culprit.
HOPE IT HELPS.