You will be given a definition of a task first, then an example. Follow the example to solve a new instance of the task.
In this task, you're given passages that contain mentions of names of people, places, or things. Some of these mentions refer to the same person, place, or thing. Your job is to write questions that evaluate one's understanding of such references. Good questions are expected to link pronouns (she, her, him, his, their, etc.) or other mentions to people, places, or things to which they may refer. Do not ask questions that can be answered correctly without understanding the paragraph or having multiple answers. Avoid questions that do not link phrases referring to the same entity. For each of your questions, the answer should be one or more phrases in the paragraph, and it should be unambiguous.

Passage: Nearing London, Oliver encounters Jack Dawkins, a pickpocket more commonly known by the nickname the "Artful Dodger", and his sidekick, a boy of a humorous nature named Charley Bates, but Oliver's innocent and trusting nature fails to see any dishonesty in their actions. The Dodger provides Oliver with a free meal and tells him of a gentleman in London who will "give him lodgings for nothing, and never ask for change". Grateful for the unexpected assistance, Oliver follows the Dodger to the "old gentleman's" residence. In this way Oliver unwittingly falls in with an infamous Jewish criminal known as Fagin, the gentleman of whom the Artful Dodger spoke. Ensnared, Oliver lives with Fagin and his gang of juvenile pickpockets in their lair at Saffron Hill for some time, unaware of their criminal occupations. He believes they make wallets and handkerchiefs.
Solution: Who believes Fagin's gang make wallets and handkerchiefs?.
Why? This question is based on the following sentence in the passage "He believes they make wallets and handkerchiefs". It evaluates the understanding that the pronoun "he" refers to name "Oliver". You can ask questions like this one about most pronouns in a paragraph.

New input: Passage: The film opens with a trio of explorers in Africa who are hiding in a cave. One of the explorers, a pregnant woman, is bitten by a vampire bat.
The film then cuts forward in time to a small European village where a series of mysterious murders are taking place. The villagers readily assemble in mob form, with torches, at the house of Professor Kristan after every murder. The villagers suspect that a giant bat is to blame for the murders. Kristan gives the villagers advice on staying safe, and assures them a scientific explanation exists.
However, in subsequent scenes, Kristan himself is revealed to be the murderer. He is seized by attacks (triggered by darkness) which transform him into a trance-like state of murderousness. After he commits a murder, he awakens from the trance with no memory of the deed, believing himself merely to have fainted.  Kristan's obliviousness is further enabled by the intervention of his loyal hunchback Zan, the only person aware of Kristan's condition. Zan follows Kristan when he is in his trances, ensuring the professor is not discovered.
An old friend of Kristan's, Dr. Bizet, arrives to visit, and soon suspects what is happening. Bizet discloses to Kristan that his mother was bitten by a vampire bat, and that traits of vampirism have likely been passed down to him per Lamarckism. (The audience now understands the pregnant explorer in the opening flashback to have been Kristan's mother.)
After Kristan's fiance is attacked by an entranced Kristan, the mob of villagers assumes Zan is culpable and chases him to the edge of a cliff inside a cave. Kristan arrives and confesses to the murders, despite Zan's protestations (aimed at saving the professor) that he, the hunchback, is in fact the murderer.  As the mob watches, Kristan throws himself over the edge of the cliff and Zan follows.
Solution:
What is the profession of the murderer?