The 50/50 Killer Chapter 4 Summary

Mark wakes from a bleak beach dream feeling crushed and despair‑laden. After a delayed morning routine he rushes to the police precinct, arrives half an hour late, and navigates a grim, gravel‑lined car park under miserable weather. Inside the reception area he is greeted by two female clerks; the left‑hand clerk smiles, hands him a clipboard, and comments on his assignment with John Mercer. Mark signs the required paperwork, exchanges brief banter about his lateness, and is photographed under a hanging black ball, producing a portrait that captures his nervous confidence. The attached file notes his background: a PhD in psychology, experience interviewing serial offenders, five years since academy graduation, and his recent appointment as a door‑to‑door investigator for Mercer's team. He proceeds to his assigned office—fifth door down—finding a dimly lit, cluttered workspace with dusty desks, stacked papers, a pile of CDs, and Mercer's own chaotic desk covered in piles of case files and a full answer‑phone. On the wall behind Mercer's desk hangs a black‑and‑white photocopied picture of Mercer receiving a civic award, scribbled with “ha! ha! ha!” by Mercer. The office phone rings; Mark answers “Detective Sergeant Mercer's office, Mark Nelson speaking.” Eileen Mercer, John’s wife, calls, teasing him as “my husband’s new servant,” and asks him to relay a vague “Don’t forget” message to John, warning that it will annoy him. Mark agrees. Shortly after, Pete Dwyer, Mercer's second‑in‑command, calls Mark, informs him that a dead body has been found in the suburbs under suspicious circumstances, and orders him to begin door‑to‑door canvassing with neighbours immediately. Mark grabs a pen, notes the details, and prepares to head out to the crime scene.