Given the task definition and input, reply with output. 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: Filmmaker Adam Green begins a documentary about artwork that features monsters.  Green is surprised when William Dekker, a retired police officer, contacts him and claims to have proof of the existence of monsters.  Green's wife reacts skeptically, but he reworks his documentary to focus on Dekker and his efforts to expose the monsters' underground home, which he calls "The Marrow". Green interviews Dekker at his house, who claims that he has seen many monsters and identified some of them through sketches. Dekker mentions his son once but diverts from the topic when Green inquires. The shooting crew of Green and his cameraman wait at the Marrow's entrance; a dug-up hole in the cemetery in the woods. On the first night they do not see anything although Dekker keeps claiming that he could see one of the monsters.
What is the full name of the person the police officer contact about monsters?