“Twin Peaks” was a groundbreaking TV series that revolved around multiple themes: sawmill intrigue, Tibetan mysticism, teenage antics, lavish donut displays, the endless pursuit of silent drapes, and at its heart, the gripping mystery of who killed small-town darling and homecoming queen Laura Palmer (Sheryl Lee). After almost two seasons filled with red herrings and diversions, the truth was unveiled in Season 2, Episode 7 (“Lonely Souls”), when it was revealed that her devoted father, Leland Palmer (Ray Wise), was the killer, albeit under the control of an evil entity named Bob.

In the Season 2 opener “May the Giant Be With You” (“Episode 8”), it was disclosed that FBI agent Dale Cooper (Kyle MacLachlan) had already determined that Laura’s murderer was demonically possessed by Bob (Frank Silva), an evil interdimensional being that thrives on his victims’ anguish. In “Lonely Souls,” Leland’s possession is exposed as his face morphs into Bob’s, leading to the vicious attack and murder of Laura’s identical cousin Maddy (also played by Sheryl Lee). The series further reveals that Leland’s possession commenced during his childhood, and while under Bob’s influence, he had spent years sexually abusing his daughter.

Before the major revelation, the cast remained unaware of Laura’s true killer. Ray Wise, who at the time was the father of a young daughter, later shared with AV Club, “The thought of a man being the murderer of his own daughter was anathema to me,” admitting, “I didn’t want to be the murderer.”

On the road to the big reveal of Laura’s killer, the show teased a long list of potential suspects as Agent Dale Cooper worked his way through Laura’s troubling diary. Smart aleck jock and Laura’s official high school boyfriend Bobby Briggs (Dana Ashbrook), who was known locally for his outbursts and hot temper, was an initial suspect, and his attitude in police interviews didn’t do much to help his case. Nor did the fact that he was sneaking around with married Double R Diner waitress Shelly Johnson (Mädchen Amick) or secretly dabbling in drug running. Laura’s secret relationship with sensitive biker heartthrob James Hurley (James Marshall) also first landed him on the suspect list. 

Another early potential suspect was Harold Smith (Lenny Von Dohlen), Laura’s agoraphobic orchid-loving friend with an interest in secretly recording folks without their knowledge. Harold starts to look especially sketchy after Donna (Lara Flynn Boyle) and Maddy discover he has Laura’s secret diary, and then he dies by suicide, surrounded by pieces of it. Ethically messy therapist Dr. Lawrence Jacoby (Russ Tamblyn) is another questionable figure in Laura’s life, particularly given his boundary-crossing relationship with the girl. 

Due to their connection to the local organized crime syndicate and brothel/casino, One-Eyed Jack’s, Cooper also considered the Renault brothers Jacques (Walter Olkewicz) and Bernard (Clay Wilcox), drug-dealing big rig driver Leo Johnson (Eric DaRe), and Great Northern Hotel owner Ben Horne (Richard Beymer).

Although the series might feel like a straightforward murder mystery in the beginning, the entire “Twin Peaks” timeline is threaded with supernatural horror elements that become more pronounced as the series progresses. Agent Cooper’s openness to mysticism and the supernatural makes him the perfect FBI investigator for the job as he begins to connect with the otherworldly elements inhabiting the woods (and the owls) of Twin Peaks. Through Cooper’s visions and his association with former partner Windom Earle (Kenneth Welsh), Cooper learns of the White Lodge and Black Lodge, two surreal extradimensional realms of good and darkness, respectively. 

Malevolent spirits like Bob that feed on humanity’s suffering (called “garmonbozia”) and what appear to be evil doppelgängers appear to reside within the Black Lodge, often lingering around its red-curtained waiting room. Here, language sometimes runs backward, spirits speak in riddles, and time appears to operate out of synch with the human world. Bob and his fellow evil spirit buddy, Mike the one-armed man (Al Strobel), appear to hail from the Black Lodge. Although Mike ultimately becomes a helpful spirit after cutting off his tattooed arm in repentance, his arm evolves into an evil entity all its own in “Twin Peaks: The Return.”