Who dunnit?

You are a detective in the story. You will be interviewing the suspects, knowing each of their point of views. Make up a conclusion on who the thief really is and why he stole it/did it. The story starts with the Doyle family’s treasure stolen. Meet four of the suspects including one of the Doyle’s as well. Find out who stole the treasure and why he/she stole it/did it.