Kim Yoon Suk*, a restaurant owner, married local theater actress Choi Sung Hee in late 2015. They resided in an apartment in Busan, South Korea.
Both were in their 30s and awaiting the arrival of their first child, as Choi Sung Hee was a few months pregnant.
On May 27, 2016, Choi Sung Hee attended a drama class and stopped by a local convenience store on her way home while her husband spent the night out drinking with coworkers. CCTV in the apartment building’s elevator captured Choi Sung Hee returning home around 11:30 p.m. and Kim Yoon Suk coming home between 3 a.m. and 4 a.m. on May 28, 2016.
The couple vanished afterward, but CCTV footage never showed them leaving their apartment. There are reportedly 21 security cameras around the apartment block, and none captured the couple.
Kim Yoon Suk’s father called the police on May 31, 2016, to report the missing couple when he had not heard from his son for several days.
Police discovered that somebody had used the couple’s cell phones several times starting May 28, 2016. According to Suzy Gardner of KoreaBoo.com, Choi Sung Hee or someone else texted her assistant director that she would not be at the next day’s rehearsal because she was ill. The assistant director received another message on May 30, 2016, stating that Choi Sung Hee could not perform as she had been admitted to the hospital due to an accident “like last time.” The texter likely referred to a previous hospital stay when Choi Sung Hee had overdosed due to depression.
The assistant director was suspicious of the text messages because Choi Sung Hee usually texted casually, but the last few contained formal language.
The assistant director later contacted someone claiming to be Kim Yoon Suk. However, he could not identify the voice because he had never spoken with Kim Yoon Suk. He later told the police the man on the phone explained that Choi Sung Hee was in the hospital.
Investigators found no hospital records of Choi Sung Hee’s admission.
Kim Yoon Suk’s employees said he called the restaurant and sounded exhausted. He said he would be off work indefinitely and sent funds to keep the restaurant operating. Some reports say the employees said the caller did not sound like Kim Yoon Suk. Police do not believe he was the caller.
On June 2, 2016, the couple’s cell phones shut off. Phone records placed Kim Yoon Suk’s phone in Busan that day and Choi Sung Hee’s phone in Seoul, roughly 250 miles away. This led Busan police to investigate the couple’s disappearance and search their apartment officially.
There were no signs of forced entry or a struggle. The police first believed the couple left on vacation because their computers, passports, phones, and wallets were not in the apartment. Dirty dishes sat in the sink. The groceries Choi Sung Hee had purchased were still in the bag on the counter, and some remained in her car in the parking garage. The couple’s dog had been left alone without food and water, and dog feces covered the floor, suggesting they had not planned to disappear.
Investigators had a mystery on their hands, no doubt. How could a couple disappear without a trace?
Over 70 officers viewed the CCTV footage, and not one could find the couple in any images. Police ultimately concluded the couple might have left their apartment through CCTV blindspots. Security cameras did not cover the emergency stairs to the first floor. However, one camera at the entrance to the stairs had a small blindspot, and the couple could have walked underneath the camera.
If others were responsible for the couple’s bizarre disappearance, police said they had to be familiar with the camera angles, which suggests there was no struggle of any kind, or else the camera would have captured it.
However, their theory does not explain why the couple was not seen on city cameras outside the apartment building. Busan reportedly has nearly 800 cameras.
There appeared to be no motive to harm the couple until investigators dug deeper into their past.
The primary suspect is Kim Yoon Suk’s ex-girlfriend, known only as Yoon. They broke up because of feuds between their families. However, Yoon still loved Kim Yoon Suk, but she married another man. He divorced her a month later, believing she had an affair with Kim Yoon Suk.
Yoon remarried again, and she and her new husband relocated to Norway. She suffered a miscarriage and contacted Kim Yoon Suk again, blaming him for ruining her life. Emotionally unstable, she reportedly sent threatening texts to him and Choi Sung Hee.
A possible motive for Yoon to harm the couple is jealousy over his marriage to Choi Sung Hee and her pregnancy. “But Kim Yoon Suk’s coworkers revealed that they believed he had a second phone, kept hidden from his wife, that he used to talk to Yoon,” writes Gardner.
Police discovered Yoon had traveled to South Korea on May 5, 2016, shortly after Choi Sung Hee announced her pregnancy. Yoon did not reveal to family or friends that she was returning to Busan, where she stayed in jjimjilbangs (bathhouses) and motels, paying cash.
Yoon flew back to Norway on June 7, 2016, earlier than planned and five days after the police began their investigation. Police tried extraditing her with the help of Interpol. However, they had no evidence tying her to the disappearance, so Norway officials ruled in Yoon’s favor against extradition.
On March 11, 2019, police asked all media outlets to publish the couple’s photos and descriptions, hoping the public would provide information.
The leading theory is that Yoon was somehow involved in the disappearance. She harmed the couple, or she and Kim Yoon Suk killed Choi Sung Hee and fled together.
Another theory is that Kim Yoon Suk and his wife left together, possibly fearful for their lives, somewhere where Yoon would not find them, and they could live a quiet life as a family.
Police also are not ruling out that a random stranger harmed the couple.
*Some sources list Kim Yoon Suk as Jeon Min-geum and Quan Min-geun and Yoon as Jang.
True Crime Diva’s Thoughts
The following views are strictly the author’s.
This case is weird, starting with no CCTV footage of the couple leaving their apartment. I don’t believe they fled the area together because they left their dog alone.
Whoever texted Choi Sung Hee’s assistant director KNEW to contact him regarding her absence. Her husband would know, and he likely told Yoon if he was still in touch with her.
What I find interesting is Kim Yoon Suk’s phone call to his employees, who said he sounded exhausted. His employees would recognize his voice. He would have been tired after being out most of the night, and he could have been emotionally exhausted as well.
Jealousy and rage can mess with certain people. So, I could see Yoon knocking on the apartment door, and Choi Sung Hee answered, maybe thinking it was her husband coming home early. Maybe Yoon knew how to get around the cameras, although I’m not sure she was familiar with the building.
I want to lean toward the theory that Kim Yoon Suk and Yoon were in this together, and they killed Choi Sung Hee. The couple had only been married MONTHS. I do not know how long they dated before the wedding. Maybe Kim was unhappy about the pregnancy and still harbored strong feelings for Yoon.
Did Kim Yoon Suk really hang out with coworkers that night, or was he with Yoon? He’s carrying a small black bag, as you can see in the CCTV footage. What is in the bag? Did the police find it during their search?
But how did they get her body out of the building without any cameras capturing them? For that matter, if he and his wife are dead, how did their killer(s) get both bodies out?
Yoon returned to Norway, and there was no evidence suggesting Kim was alive and had followed her. So, I think she likely killed both and had help. I would wager her family was involved, or at the least, had knowledge of her involvement. A couple of sources reported that Yoon’s mother tried to get her to return to Busan and speak to the police, but Yoon refused.
“6 Scary Unsolved Crimes In Korea,” by Angelli.
“Newlyweds missing case, unsolved disappearance in Busan,” by Juliane Cunha.
“True Crime Korea: The Mystery of the Disappearing Newlyweds,” by James Maines.