Elements of Detective stories

1. A detective story typically requires:
2. A detective, professional or amateur
3. A criminal, usually a murderer
4. A victim, usually of murder (often the least likely suspect)
5. A number of suspects (a) and/or witnesses (b)
6. The criminal's means
7. The criminal's motive
8. The criminal's opportunity
9. Clues
10. Red herrings (a) and other distractions (the latter, b, of which often occur because of the behavior of the detective or other characters)
11. Inferences (a) or explanations (b) regarding clues or red herrings, which may not always be shared with viewers (or readers)
12. Interrogations of (a), or conversations with (b), suspects and witnesses.
13. The withholding of the context that explains the mystery
14. The solution to the mystery, provided by the detective
15. A sidekick for the detective, as a stand-in for viewers (or readers) (e. g., Dr. Watson or Columbo's “bumbling” persona, which is the “sidekick” to Columbo's true, capable detective abilities)
16. The police's alternative theory concerning (i. e., solution to) the crime
17. An intricate plot
18. A group activity that provides both the setting, the victim, and the suspects for the murder (this is particularly discernible in The Brokenwood Mysteries)
19. Alibis that either clear a suspect of murder or seem to do so
20. Two stories in one: what appears to have happened and what, in fact, occurs (Monk very clearly separates these two stories, by having Monk's explanation begin, “Here's what happened.”)

Fandom wikis often provide detailed summaries of the plots of detective show episodes that can be used to illustrate the use of these elements. This is a slightly modified summary of a Monk plot:

Mr. Monk Goes to the Office [16]

In a parking garage [7], a shadowy male figure [2] is seemingly changing a tire on his car. A security guard, Ronnie Shelton [3], confronts him, telling him that the vehicle is not his car, and takes out his cellphone, planning to call the police. Before he can call, the man shoots him twice in the chest with a .45 caliber gun [5], drags his body underneath a nearby parked truck, and comes back to the car, waiting. Soon, financier Warren Kemp walks into the garage, talking on his cellphone. As, finishing his call, he approaches his car, the man comes at him from behind, points the gun at his back, and orders him to open the front car door and put his right hand in it, which Kemp does. Then the man closes the car door, breaking Kemp's hand [8], and runs away, leaving Kemp to scream in terror and agony.

At the crime scene, Adrian Monk [1] tries to talk with other police officers, using prepared notes, but he fails every time. Then he and Natalie [14] go to Captain Stottlemeyer, who recounts what happened: a man killed the security guard (they found gun shells[8]), then waited for Kemp and broke his right hand. Monk notices a wrench [8] found near one of the cars and figures out that it doesn't match the wheel bolts of that car [10a], so the killer obviously took it with him so he could pretend he was changing a car wheel while waiting for Kemp [10a]. The wrench also makes it apparent that he drives a European car (since the wrench is metric, and all cars in parking lot are American [10a]). He also finds a toothpick near the car tire, which the killer had been chewing [8], and says that the killer (judging by that) wants to boost his ego [10a] (but later says he's just guessing, when he sees that Stottlemeyer is chewing a toothpick as well [10b]). Soon, Kemp notices Natalie and takes an interest in her [9b]. The paramedic says that Kemp must go to the hospital, but Kemp wants Monk to go to his office the next day, along with Natalie.

The next morning, while waiting for Kemp, Natalie says she used to have the kind of job he has, but she soon quit because she hated doing the same things every day and start feeling like a number. Although she believes that type of job is terrible, Monk seems to enjoy it [9b].

They talk to Kemp [11b]. Monk is upset because Kemp broke nine bones during the attack (he wished that Kemp had broken ten [9b]). Due to imprints on the carpet [8], Natalie figures out that furniture was recently moved to the opposite side from which it was originally [10a]. Kemp says his decorator Angela Dirks did that [10b], and also mentions that he talks about very important things here [6] and the security company comes every two weeks looking for microphones and other listening devices [10b]. He says he's very scared and paranoid that the killer is someone close to him and asks Monk if he will go undercover in the office [17]. Natalie says he couldn't do that, but Monk accepts the offer.

Sometime after, Monk goes into the office [17] undercover. One of the employees, Annette [4a], takes him to his cubicle. During the walk, Monk tries to solicit information about the incident [11b], but he doesn't find out much. One employee, a strange guy named Chilton [4a] argues about why Monk took the spot at the office which he wanted, but Annette defends Monk [9b]. Chilton later collects money for the celebration of his own 40th birthday [9b].

At the police station, Lieutenant Randy Disher comes up with a very plausible theory: it seems that there's been an inside man who was selling important financial information, and Kemp was the suspect [15]. There's possibility that Kemp was cooperating with the killer, they argued and the killer breaks his hand as the warning, killing the security guard in process [15].

Back at the office, all the employees are going to a restaurant at the bottom of the building using the elevator. Monk promises to go with them, but he doesn't enter the elevator, and he lies saying that he will waiting for another one. Then he meets Kemp and Natalie, and he reveals that he didn't learn anything. After Monk leaves, Kemp offers to go to his office with Natalie, and she agrees [9b].

At the restaurant, as the employees are eating nachos, Monk is only pretending to eat (since they're all touching nachos, and he is a germophobe) [9b]. He also reveals that Annette and one other employee, Greg [4a], are a couple [9a], and starts calling his new friends “the office crowd.”

Meanwhile, Kemp and Natalie are hanging out and are getting even closer to each other [9b]. She even mentions that, in a bar in Vermont, she beat up a guy who was annoying her friend [9b].
Later, when Kemp meets Monk, Monk agrees to go bowling with the other employees to see if he can learn anything new. He also notices that Chilton is chewing a toothpick [8], just as the killer did [8].
In the hall, Natalie hears two women talking about her and saying that she almost killed some guy in Vermont and sent an email about it to the whole staff. She concludes that Kemp leaked that information and confronts him. He denies everything, but she doesn't believe him [9b]. She and Monk also reveal that Chilton has an alibi [18].

During the game, Chilton points out that Monk doesn't wear special bowling shoes, and that he shouldn't play. Other employees try to make him wear the bowling shoes, but he refuses because somebody else was wearing the shoes. The other team wins [9b].

Back in the office, Monk says he bought the bowling shoes, but other employees are still very cold to him. The only one that seems willing to talk to him is Angela, albeit to get his opinion on what color he likes for new curtains that she is planning to put in [8].
Late at night, a shadowy male person [2], who chews a toothpick [8], enters the decorator's place and shoots her once [5], killing her, and uses a pillow as a silencer [5].

The next day, Stottlemeyer and Disher are on the crime scene. Disher says that Angela worked for the same company for which Kemp works, and that the killer and weapon are probably the same [10a]. The toothpick [8] is also found.

“The office crowd” goes into the Chinese restaurant without Monk. [9b] He goes down the building to another restaurant [7] with Natalie. Natalie says that there must be a connection between two homicides [10a]. When Monk sees the man sitting opposite from them [4], who has a hearing aid [8], constantly look into Kemp's window [8] and write notes down on paper [8], Monk solves the case.

Here's What Happened

Monk smiles strangely, so his lips won't move, and gives the summation [13]:

That man can read lips [10a] and he discovered that he could see Kemp's window through the restaurant's window [10a, 12]. By watching Kemp as he talked to clients, he found out a lot of important business information [10a, 12], allowing him to make plenty of money [6, 12]. But when Kemp's furniture was rearranged, Kemp's right hand covered his mouth while talking on the phone [10a]. So, the killer needed Kemp to change hands [6]. He also killed Angela (the decorator) because she wanted to put in curtains that would have put a permanent kibosh on his racket [6, 10a].

Unfortunately, the killer saw Natalie in the mirror and read her lips [12]. He comes to her and Monk and shows them a gun. He wants them to go out, but Natalie screams into his ear and Monk takes his gun. Natalie calls the police.

Later, Natalie tries to continue her relationship with Kemp, saying that the killer probably saw them and sent an e-mail to make them fight [10a], but she fails to get him back, walking out with Adrian as he packs his desk.

Knowledge of the elements typical of the detective story can help viewers (or readers) to solve the mystery themselves as they follow the detective's investigation of a case, provided that information that the story withholds from viewers (or readers) is not so vital to the mystery's solution as to prevent them from inferring the significance of the clues offered along the way. Sometimes, the relationship between the killer and the victim is the key to unlocking the solution, since the relationship allows the cause-and-effect link between the murder and its motive. For example, a killer and a victim may be related through marriage, and the killer may murder his wife because she is unfaithful to him. Alternatively, for the same reason, the cuckolded husband may kill the adulterous lover, rather than his wife or both his wife's lover and his wife. It is from their relationship that his motive, revenge, arises.

Note: The episode summary is borrowed, with permission, from the Fandom Monk Wiki, which operates under the provision of the Fandom “Community Creation Policy” that stipulates that “text on Fandom communities is available under a free content license, meaning the information you put on the wiki can be copied and reused by anyone.”