Who Really Killed Park Hee-jung in Trap of Desire? Clues Involving Manager Na and Joo Mi-ran Ahead of Episode 20
As of the morning of 2026-09-04, the identity of Park Hee-jung's killer in 'Trap of Desire' has not yet been definitively established in the aired episodes. However, episode 19 revealed that Manager Na's alibi had been fabricated, and his connection to false witness Lee Jung-tae was also confirmed, making him one of the leading suspects.
The preview for episode 20 takes the investigation a step further. Go Eun-seol becomes increasingly convinced that Manager Na is involved, while Cha Seok-jin discovers suspicious notes about Go Eun-seol in Manager Na's notebook. As the longstanding relationship between Joo Mi-ran and Manager Na comes back into focus, the central question is shifting from 'Is Manager Na the killer?' to 'Who was Manager Na acting for?'
Why Is Manager Na the Leading Suspect?
The clearest clue established so far is that Manager Na's schedule on the day of the murder was not an authentic record.
In episode 19, Go Eun-seol reexamines a scheduled off-site meeting that Manager Na supposedly attended with an advertising agency representative around the time of Park Hee-jung's murder. While examining the agency representative's diary, she notices that the entry for the day of the murder differs from the other appointments in both handwriting and the condition of the pen markings. This raises the possibility that the appointment was added afterward. KBS also explicitly states in its official preview for episode 20 that Go Eun-seol discovers Manager Na's alibi was fabricated.
An alibi is evidence showing that someone could not have been at the crime scene at a particular time. But if the alibi itself was deliberately manufactured, the situation changes completely.
Investigators must establish where Manager Na actually was at the time of the murder and explain why anyone needed to create a false appointment in the first place.
However, a fabricated alibi does not automatically mean that Manager Na is the murderer. He may have participated directly in the crime, but it is also possible that he falsified his whereabouts to protect someone else.
False Witness Lee Jung-tae Has Already Been Linked to Manager Na
Suspicion surrounding Manager Na did not suddenly emerge from the discovery of his fabricated alibi.
Lee Jung-tae is one of the key figures who helped frame Go Eun-seol for murder by acting as a false witness. In an earlier episode, Go Eun-seol followed Lee Jung-tae's movements and witnessed him meeting Manager Na, a close associate of Joo Mi-ran.
The developments revealed so far can be connected as follows.
Park Hee-jung dies
→ Go Eun-seol is accused of murder
→ Lee Jung-tae appears as a false witness whose testimony implicates Go Eun-seol
→ A connection between Lee Jung-tae and Manager Na is subsequently confirmed
→ Manager Na's alibi for the day of the murder is also revealed to have been fabricated
Manager Na has therefore become more than merely a suspicious company employee. He is now a key figure who may connect Park Hee-jung's murder to the plot to frame Go Eun-seol.
Nevertheless, this connection is still not direct evidence that Manager Na murdered Park Hee-jung. What has been established so far is circumstantial evidence linking him to the false witness and the fabricated schedule.
Could Joo Mi-ran Be the Real Killer?
Joo Mi-ran is another figure who cannot be overlooked when investigating who may be behind the crime. However, as of the morning of September 4, it has not been confirmed that Joo Mi-ran personally murdered Park Hee-jung.
The drama has already shown direct contact between Joo Mi-ran and Lee Jung-tae, including a scene in which Lee Jung-tae makes a new proposal to her. Manager Na has also consistently been portrayed as one of Joo Mi-ran's close associates.
More importantly, the official preview for episode 20 introduces another significant development.
Joo Mi-ran takes an anxious Manager Na to a place where the two spent time together long ago. The preview description released by KBS directly suggests that their relationship stretches back into the past. However, the preview does not reveal what happened at that location or the exact nature of their previous relationship.
For now, rather than treating Joo Mi-ran as the 'confirmed killer,' it is more accurate to regard her as someone whose knowledge of, or possible influence over, Manager Na and the false witness needs to be investigated.
Why Was Go Eun-seol Framed for Park Hee-jung's Murder?
Park Hee-jung is Go Eun-seol's adoptive mother, who raised her as though she were her biological daughter. Park Hee-jung's death directly triggered the collapse of Go Eun-seol's life.
According to the officially released character profile, Go Eun-seol was framed for murder through a trap designed by someone else. After spending her 20s in prison, she was released 10 years later and entered Cheongma Group to uncover the truth.
The ongoing investigation is therefore about more than simply identifying the person who killed Park Hee-jung.
The actual murder
→ Recruitment of a false witness
→ Concentration of suspicion on Go Eun-seol
→ Fabrication of an involved person's alibi
To explain why Go Eun-seol was framed for murder, it is necessary to determine how much of this sequence was planned from the beginning.
This is also why Manager Na's fabricated appointment matters. Establishing his actual whereabouts could help reveal not only what happened on the day Park Hee-jung died but also how Go Eun-seol was framed.
3 Key Clues to Watch for in Episode 20
Episode 20 is scheduled to air on 2026-09-04, so as of 11 a.m., the episode has not yet aired and no conclusion has been revealed in the broadcast. Rather than identifying the killer based solely on the preview, viewers should pay attention to three specific developments.
First is Manager Na's actual whereabouts on the day of the murder. If the supposed meeting was fabricated, the most important unanswered question is where Manager Na really was during that time.
Second is the information about Go Eun-seol recorded in Manager Na's notebook. In the preview for episode 20, Cha Seok-jin discovers suspicious notes concerning Go Eun-seol in Manager Na's notebook. Their significance could change considerably depending on whether they were written before or after the murder.
Third is the past relationship between Joo Mi-ran and Manager Na. Whether the 'place where they spent time together long ago' is connected to Park Hee-jung's murder or the framing of Go Eun-seol will be central to the next developments.
What Has Been Confirmed So Far?
As of 11 a.m. on 2026-09-04, the identity of the person ultimately responsible for Park Hee-jung's murder in 'Trap of Desire' has not yet been confirmed.
However, the evidence surrounding Manager Na has grown more suspicious on two fronts: his connection to false witness Lee Jung-tae and the discovery that his alibi for the day of the murder was fabricated. Joo Mi-ran is also linked to both Lee Jung-tae and Manager Na, making her an important figure in uncovering who may be behind the crime.
The most accurate conclusion at this point is therefore 'Manager Na is a leading suspect, but neither Manager Na nor Joo Mi-ran has been definitively identified as the person who murdered Park Hee-jung.'
After episode 20 airs, it will be important to distinguish between potential murder suspects and those who may have orchestrated the crime, depending on whether the episode reveals Manager Na's actual whereabouts, the notes about Go Eun-seol in his notebook, and the past shared by Joo Mi-ran and Manager Na.