Electronic anklet defacement and serial murders in Songpa-gu, South Korea, 2021

 In late August 2021, a 56-year-old male named Kang Yoon-seong, who had a history of robbery and sexual crimes, committed a series of murders against two victims in the Songpa-gu district of Seoul, South Korea. Afterward, he turned himself in to the police.

On August 26th, around 5:00 PM, Kang Yoon-seong purchased a kitchen knife from a mart in Samjeon-dong, Songpa-gu. Prior to that, at 3:57 PM, he bought a cutting machine from a hardware store in Ogum-dong. Between 9:30 PM and 10:00 PM on August 26th, Kang Yoon-seong suffocated and killed a woman in her 40s whom he had met at a karaoke establishment, using a blanket.

He claimed that he killed her because she refused to engage in sexual intercourse. The body of this woman was not discovered until Kang turned himself in. The police had visited Kang's residence five times, including on the day he damaged his electronic ankle monitor, from 6:00 PM on the 27th to 2:00 AM on the 28th, but they did not uncover the first murder. A police official stated, "There may be legal and institutional limitations on entering residential areas," and expressed regret that the on-site officers did not exercise more proactive police authority.

At 11:30 PM on August 26th, Kang urgently called someone named "A" (a different person from the 2005 incident mentioned above) and said, "The woman is injured. There is blood all over my hands. This happened because you didn't give me money. Lend me some money. I haven't eaten anything today. I bought an industrial cutting machine." On the early morning of August 27th at 12:14 AM, when the electronic ankle monitor violation alarm went off, the Crime Prevention Team immediately responded and confirmed the violation.

However, by the time they arrived at the scene at 12:34 AM, Kang had returned home, and the restriction on his movements had already ended. The Crime Prevention Team notified that they would summon and investigate him regarding the violation in the future. During the phone conversation with the Crime Prevention Team, Kang stated, "My girlfriend felt sick, so she went to the convenience store to buy some medicine"

On the morning of August 27th, around 10:00 AM, Kang Yoon-seong called the Seoul Eastern Probation Office and stated that he wanted to speak with his assigned probation officer. Since the probation officer was not available, a colleague answered the call. Kang asked for leniency, explaining that he had unavoidably violated the restriction on his movements. The colleague informed him that strict investigations must be conducted for such violations and instructed him to attend on the following Monday (August 30th).

At around 12:00 PM on August 27th, Kang Yoon-seong discarded the victim's cellphone in the garden of a villa located in Bangi-dong, Songpa-gu. The police discovered this cellphone on August 31st.

At 5:31 PM on August 27th, Kang Yoon-seong used an industrial cutting machine to damage his electronic ankle monitor in an area with sparse human traffic in Sincheon-dong, Songpa-gu. He then discarded the ankle monitor in a garden next to the entrance of Mongchontoseong Station on Line 8, about 100 meters away. Afterward, he fled to Seoul Station using a black G80 (DH) rental car that he borrowed by paying money in Yongsan-gu. The alarm was triggered at 5:31 PM, and the control center personnel immediately notified the situation room and the Seoul Eastern Probation Office.

Two staff members from the Electronic Monitoring and Crime Prevention Team of the Seoul Eastern Probation Office arrived at the final location of the damage at 6:00 PM on the same day and began searching, but they did not find Kang. At 5:37 PM, the Ministry of Justice requested cooperation from 10 probation offices and corresponding police stations in the Seoul and Gyeonggi area for apprehension.

They also deployed staff members to expected hideout areas and major terminals. The staff members confirmed the movement route through mobile phone tracking of the subject. They visited Kang Yoon-seong's residence three times with a two-hour interval but did not discover the body of the woman in her 40s. At 9:00 PM, they confirmed the rental vehicle information and conducted a search using the Wanted Vehicle Search System (WASS) and vehicle tracking.

At around 11:50 PM on August 27th, the first tracking team, the Special Judicial Police from the Ministry of Justice, belatedly applied for an arrest warrant to the prosecutor's office. However, the duty office of the Seoul Eastern District Prosecutors' Office returned them, stating, "It's late at night, so come back tomorrow morning when the decision to file charges will be made."

On August 27th, the exact time is uncertain, but Kang Yoon-seong purchased four iPhones worth a total of 5.96 million won using the victim's credit card at a mobile phone store in Gangnam-gu and then sold them to obtain money.

On the morning of August 28th, at 9:00 AM, as the car rental company began its operations, they initiated real-time GPS tracking to determine the location of the vehicle and started the pursuit. At 9:18 AM on August 28th, Kang Yoon-seong abandoned the vehicle near Seoul Station and fled. He was wearing a gray short-sleeved t-shirt and black background sneakers.

CCTV footage showed Kang Yoon-seong exiting the car and walking along the sidewalk. Meanwhile, a police officer discovered the rental car. Kang Yoon-seong seemed to be heading back towards the car, but upon noticing the police officer standing near the vehicle, he quickly turned around in surprise and walked in the opposite direction. It was a close call, as he narrowly avoided being apprehended by just a 6-minute difference and 20 meters away.

Later, Kang Yoon-seong had another conversation with individual A. When A advised him to surrender, Kang Yoon-seong became angry and then mentioned, "There's a person who turned drinking into a game near the playground. I checked their wallet and they had no money, there's a public restroom, right? It's just theft anyway, not robbery." He claimed to have stolen someone's credit card.

At 9:20 AM on August 28th, the Ministry of Justice applied for Kang Yoon-seong's arrest warrant to the prosecutor's office. In the afternoon, at 2:00 PM, the Seoul Eastern District Prosecutors' Office requested Kang Yoon-seong's arrest warrant from the Seoul Eastern District Court. It was a somewhat delayed response.

Kang Yoon-seong traveled from Seoul Station to Boramae Station in Yeongdeungpo-gu and boarded a bus, discarding his smartphone on the bus during the process. He then got off at Munrae Station in Yeongdeungpo-gu and took the subway to Gimpo Airport Station.

In the afternoon of August 28th, Kang Yoon-seong called a woman in her 50s, whom he knew through social activities, and suggested they go for a drive together. They traveled around Gyeonggi Province and various parts of Seoul in her car. During this time, Kang Yoon-seong asked the woman for money, but she refused. #It was revealed that Kang Mo, the woman in her 50s, had previously borrowed 20 million won from her and had not repaid it. As a result, the woman demanded repayment.

While on a drive, Kang Mo visited Palgakdam in Hanam City and then returned to Songpa-gu. Around 3:00 AM on August 29th, Kang Yoon-seong returned to Songpa-gu again and murdered a woman in her 50s inside the car he had parked near the road close to Jamsil Hangang Park in Songpa-gu.

Kang stated, "I owed a debt to the woman in her 50s, and although I intended to repay at least a portion, she pressured me to pay it all, so I killed her." Subsequently, on August 29th at 7:55 AM, as the police net closed in, Kang Yoon-seong drove the vehicle with the deceased woman in the back seat and went to the Songpa Police Station, where he confessed to the murder. #This was before the arrest warrant was issued.

On August 31st, when Kang Yoon-seong left the Seoul Songpa Police Station after his detention hearing, he displayed a remorseless attitude and shouted at journalists questioning him about his motives, demanding fair reporting. When asked if he committed the crime for money, he became agitated and threw the microphone of a reporter, expressing his frustration. Even as he boarded the escort vehicle, he shouted at the journalists, "You reporters twist the news... People need to know the truth!"

Even after arriving at the Seoul Eastern District Court, where the detention hearing was scheduled for 10:05 AM, Kang Yoon-seong kicked the broadcast microphone with his foot in response to a reporter's question, "Why did you kill the victim?" The microphone, deflected by Kang's action, struck a reporter's forehead.

Furthermore, just before entering the building to avoid the journalists' barrage of questions, he verbally abused them, saying, "Do your reporting properly!" #On August 31st, at 11:21 AM, after completing the warrant hearing, Kang Yoon-seong emerged and made offensive remarks in front of the journalists, saying, "Society has made me like this.

It's a pity I couldn't kill more." Chief Judge Shim Tae-gyu, who presided over the warrant hearing at the Seoul Eastern District Court, proceeded with the hearing for Kang, who faced charges of violating the electronic tracking device law and murder, and subsequently issued a detention warrant, stating, "There is concern that he may flee."

On September 2nd, the Personal Information Disclosure Review Committee decided to disclose Kang Yoon-seong's personal information. #However, there is controversy as the photo of the disclosed resident registration card looks significantly different from the actual appearance reported by the media, to the point where even residents from the same neighborhood cannot recognize him, raising doubts about the appropriateness of the information disclosure.

Subsequently, on September 7th, he was handed over to the prosecution. Then, on September 24th, he was indicted and arrested for robbery and murder, fraud, and violation of the electronic tracking device law. The prosecution referred to Kang Yoon-seong as a psychopath. #According to the information revealed later, Kang Yoon-seong scored in the 30s, which is at a similar level to Yoo Young-chul and Jung Nam-gyu, indicating an extremely severe level of psychopathy. In a related article, before the first trial on October 14th, he also sent a letter to his defense attorney requesting the death penalty.

Kang Yoon-seong was immediately detained, and initially, there were considerations to charge him with damaging an electronic monitoring bracelet and murder. However, it is now under review whether to apply the more severe charge of robbery and murder, which carries a minimum sentence of life imprisonment and a maximum penalty of death. The murder charge carries a minimum sentence of more than 5 years, while robbery and murder start at a minimum sentence of life imprisonment and can lead to the death penalty.

Since he planned and committed the murders of two individuals, establishing a pattern of serial killings, the likelihood of a minimum sentence or even the death penalty is high. However, the fact that he expressed remorse and surrendered himself could act as a variable. Considering that Jang Ja-jin is the only civilian who has received the death penalty since the 2010s, the chances of receiving a death sentence are low.

Given that Kim Tae-hyeon, the perpetrator of the No Won Three Sisters murder case, received a life sentence, it is highly likely that Kang Yoon-seong will also receive a life sentence. In the first trial on May 26, 2022, a life sentence was pronounced, and an appeal was filed on June 3. #In the second trial on September 22, 2022, the appeal was rejected, and a life sentence was confirmed. #Afterward, as there was no further appeal, the sentence became final.