The first chapter in Homicide starts as Detective Tom Pellegrini and his Squad Supervisor, Detective Sergeant Jay Landsman, are examining a murder victim. The dead man is a 26-year-old drug dealer shot twice outside some row houses in Baltimore. Pellegrini teases the uniformed officers at the scene by claiming that two of the shots may have entered the victim's body through the same entrance wound. He tries to get some information from a woman living in an adjacent building, but she refuses to talk to him. As the body is rolled into the morgue wagon, Pellegrini and his supervisor drive off. David Simon, the author, then tells us a little about the two men. Pellegrini is relatively new on the Homicide Squad but has earned a reputation as a tenacious and capable detective. Jay Landsman is also a new arrival, appointed because he served in the City Hall security detail.
Back at headquarters, Landsman erupts in anger at the witness to another homicide, calling her a liar and then charging her. She is interrogated along with other witnesses, and the night's work leads to the arrest of a missing gunman. Landsman goes home to sleep while Pellegrini continues to work on the killing of the drug dealer. He goes back to the Western District to interview a potential witness but doesn't find the testimony especially useful. Pellegrini catches a few hours' sleep at home, then returns to the station for the graveyard shift. The author then briefly describes the routine of a homicide detective, including the details they look for at a crime scene and the questions they ask themselves as they do this. All the witnesses taken downtown lie, Simon writes, and it is up to the investigating detective to sift through their lies. If nothing comes out of the interrogations, then detectives can hope for a break from lab results or a phoned-in tip. "And when the phone doesn’t ring, you let a little piece of you die," Simon continues.
He goes on to describe how a case makes its way through the courts. If a trial ends in a conviction, the assistant state attorney may buy you a beer. Simon also describes the career path of a homicide detective from patrolman to plainclothes officer to the Homicide Squad, which he calls "the major leagues, the center ring, the show" and "the natural habitat of that rarefied species, the thinking cop." The homicide detective is at the bottom of an organizational pyramid with the Deputy Commissioner and the mayor at the top. A "red ball" case is one that attracts a lot of media attention and can reflect badly on the mayor or the governor.
Such a case was the shooting of John Randolph Scott while running from the police after stealing a car. It first appeared that the bullet in John Randolph had been fired by a pursuing patrolman, but this was quickly proved wrong. The officer assigned to the case was Donald Worden, a big bear of a man and a "natural policeman." The case has gone cold for Worden, and his supervisor sent him and his young partner out on a call to give him a break. At the scene of the shooting, Worden is certain that the victim's younger brother is lying to cover up what was an accidental shooting. He returns disgruntled to his desk.
Simon catalogs the traits of a good homicide supervisor and notes that Gary D'Addario is one who relies on his detectives to perform well without needless interference or bullying. But with the first month of the year on the wane, the board that shows cleared cases and those still unsolved does not look good for him or his men. Simon explains "dunkers," cases that can be immediately closed, and "whodunits," cases presenting little evidence as to the identity of the perpetrator.
Simon continues with a case assigned to Harry Edgerton. Everything about the shooting resembles a suicide. One of the uniformed officers who took the call is a woman, and Simon recounts how women have had difficulty making it into homicide. The author describes Edgerton as a transplant from New York and a loner whose work habits irritated his colleagues. They also resented his absences while investigating links between the city's drug traffickers and homicides, even though these investigations resulted in the clearing up of several murders. Simon concludes the chapter by recounting the teasing remarks directed at Edgerton by the other detectives as he fills out a report on the suicide.