One of the interesting things about human interactions is that when humans are in groups for long enough, there's almost always a "pecking order." Sometimes the "pecking order" is set up by social class (i.e. those who are in higher social classes are "above" those who are not). Other times, the hierarchy has to do with one's work (e.g. a store manager is higher up on the ladder, so to speak, than is the assistant manager). The hierarchy may be very rigid or more flexible, but it's there. So it's no surprise that we see a lot of the "pecking order" in crime fiction, too.
In Arthur Conan Doyle's A Study in Scarlet, Sherlock Holmes and Dr. Watson investigate the strange murders of Enoch Drebber and later, his friend Joseph Stangerson. Both men are Americans, staying at a rooming house in London. When Drebber is killed, Stangerson's one of the suspects in his murder, but then, Stangerson is murdered himself, so Holmes has to look elsewhere for the killer. It turns out that these murders are closely related to the social hierarchy of the Mormon community in Utah during that time. Stangerson and Drebber were highly-placed on that social hierarchy; their murderer was not. The murderer believed that both victims took advantage of their place in the "pecking order" to commit what the murderer believes was a terrible crime.
We see a lot of the "pecking order" in Agatha Christie's novels, too. For instance, in One, Two, Buckle My Shoe (AKA The Patriotic Murders and An Overdose of Death), Poirot and Inspector James "Jimmy" Japp investigate the shooting death of Henry Morley, who happens to be Poirot's dentist. Not long after they begin their investigation, Mabelel Sainsbury-Seale, another of Morley's patients, disappears. Then there's another death. It's clear now that Morley's murder was a lot more involved than anyone thought at first. Poirot and Japp are working on the case when authorities higher up on Scotland Yard's hierarchy call off the investigation. Since Japp's not at the top of the "pecking order," he has to leave the case alone. But Poirot doesn't. He continues to slowly put the pieces of the puzzle together, and finds out who killed Morley and what happened to the elusive Miss Sainsbury-Seale. He also discovers that the murderer has taken advantage of the social and political hierarchy to "cover up" involvement in the crime. Fortunately, Poirot is not without influence himself, so he's able to catch the criminal.
In Christie's The Hollow, we see an interesting example of a smaller-scale, but no less apparent, "pecking order." In that novel, Poirot investigates the shooting death of Dr. John Christow, a Harley Street specialist who's visiting the country home of Sir Henry and Lady Lucy Angkatell for the week-end. Poirot's been invited for lunch on that Sunday, and arrives just in time to see the immediate aftermath of the murder. Since he was very nearly a witness to the crime, Poirot works with Inspector Grange to find out who killed Christow and why. At one point in the novel, kitchen maid Doris Emmitt tells one of Grange's police officers about something she's seen. When Grange finds out, he says:
"…Kitchen maids talk, kitchen maids babble. They're so kept down and in their place by the cook and the upper servants that it's only human nature to talk about what they know to someone who wants to hear it."
Shortly after Doris tells what she's seen to the police, she's upbraided by the cook, the housekeeper and the butler, all of whom are higher in the household hierarchy than she is. It's an interesting look at how hierarchies form, even in small groups.
One of the "pecking orders" we see most frequently in crime fiction is the police hierarchy. Michael Connelly's Harry Bosch and Ian Rankin's John Rebus frequently get in trouble because they don't respect the hierarchy. In fact, in Rankin's Resurrection Men, that's why Rebus is sent off to Tulliallan Police Academy; he threw a mug of tea at a superior officer and is among several police officers who have difficulty with authority. In both Connelly's and Rankin's novels, too, we see one consequence of relying too heavily on a "pecking order." Those at the top are often protected, even if what they do is reprehensible. So there's a lot of opportunity for corruption.
In Minette Walters' The Breaker, we see another example of the police "pecking order" in action. When the body of thirty-one-year-old Kate Sumner is found on the beach near Chapman's Pool, Dorset, P.C. Nick Ingram is the first police authority called to the scene. Ingram's a bright, capable officer, but he's not ambitious, and is content to be a rural constable. He sends the case along to headquarters, thirty miles from his more rural office, and is told to expect a visit from detectives who are based there. They duly arrive, and we get a look at the police hierarchy:
"The sergeant, an arrogant, pushy type…went down like a lead balloon with his rural colleague and Ingram was never able afterward to remember his name…"
After an official speech on what's required for an investigation (information Ingram already knows full well), we see how Ingram feels about the hierarchy when the sergeant says,
"'Did you get all that?'…
'I think so, sirr,' he [Ingram] said in a broad Dorsetshire burr, resisting the temptation to tug his forelock."
There's also a hierarchy across police forces. For instance, in Tony Hillerman's The Dark Wind, Sergeant Jim Chee of the Navajo Tribal Police has been assigned to investigate vandalism at a series of water towers. He's on the case late one night when he witnesses a plane crash. It turns out that the plane crash is related to drug smuggling, a mysterious dead man and the water tower vandalism. As soon as the drugs connection is clear, the FBI is called in, and the "pecking order" is clear when FBI agent Johnson accuses Chee of being in on the drug smuggling ring and being "on the take." Chee's boss, Captain Largo, does his best to protect Chee, but it's really not until Chee is able to put all of the pieces of the puzzle together that he's free of suspicion.
In P.D. Martin's Fan Mail, FBI operative Sophie Anderson has to deal with the "pecking order" when she transfers to the FBI field office in Los Angeles - and runs into a mysterious set of murders. All of the victims are crime novelists who've been killed in ways that eerily mimic their writing. Anderson has to walk a very delicate line between getting the case solved and treading on the toes, so to speak, of the L.A.P.D., who have local jurisdiction.
There are a lot more examples of the "pecking order" in action in crime fiction, both in and outside of the police hierarchy - many more than I have space for here. Which are your favourites?