This task allows you to practise grammar (tenses) and vocabulary (apperance), but also the skill of writing or speaking (or both). It depends on how you will plan your lesson. The students fill in the table, later they may give it to a friend who will guess the criminal or it may be the topic of discussion for the whole group about who is guilty. You may also ask your students to write a paragraph from their story. I was inspired by Agatha Christie's detective stories while creating this task.