Christopher’s father is the novel’s antagonist because he forbids Christopher from investigating the murder of Wellington. Initially, this advice seems wise, as Christopher does not have the emotional intelligence to navigate complicated, precarious social situations. If Christopher were to have another negative interaction with a police officer, for example, the results could be disastrous. As Christopher continues to interview his neighbors, he must hide his efforts from his father and lie about his whereabouts, which is very difficult for Christopher. When Christopher’s father finds his book and realizes how close Christopher is coming to the truth, he loses his temper, swears at Christopher, throws his book in the garbage, and strikes him. The next day, Christopher’s father feels deep remorse for hurting his son and tries to make amends by taking him to the zoo, but he still insists that Christopher stay out of the investigation.
Christopher’s father stays concerned for Christopher’s safety, and this concern significantly motivates his father’s cover-up of the long chain of lies that led to Wellington’s murder. His father’s first and most egregious deception took place two years before the opening of the novel, when he told Christopher that his mother died, when she had actually left their family to live with their neighbor, Mr. Shears, in London. After, Christopher’s father formed a close, probably romantic relationship with Mrs. Shears. When Mrs. Shears made it clear she would not stay with Christopher’s father, he became unhinged and murdered Wellington with Mrs. Shears’ garden fork. As a single parent to a child with special needs, Christopher’s father most likely lacks the appropriate outlets for his frustrations and his own emotional needs, which results in his violent temper. Christopher’s father’s many lies are misguided, frustrated attempts to protect his son from things that could hurt him, and they have disastrous consequences. In the end, when Christopher solves the mystery and moves out of his father’s house, Christopher’s father resolves to become more honest and patient so that he can rebuild the trust he lost with his son.