The National Police Agency has detected 315 online murder threats, which have surged following recent stabbing attacks, and nabbed 119 posters of such messages on internet forums and social media as of Friday.

The police said the number of online murder threats increased by 121 since Monday, and the number of posters apprehended increased by 52.

A considerable number of these posters were minors, according to police, who said that 34 people apprehended as of Monday were teens.

According to the Supreme Prosecutors’ Office, 12 suspects have been arrested across the country as of Friday for murder threats.

Of these suspects, 11 were arrested for posting murder threats online, while a 31-year-old man was arrested Monday at Dongdaegu Station in Daegu after dropping his knife while attempting to take it out from his bag.

Of these arrested suspects, five were in their 20s and four in their 30s, while two were 19 years old.

Police have been cracking down on online posts threatening copycat attacks following two recent stabbing rampages.

On July 21, 33-year-old Jo Seon went on a stabbing attack near Sillim Station in Gwanak District, southern Seoul, killing one man and injuring three others.

On Aug. 3, 22-year-old Choi Won-jong killed one woman and wounded 13 others after he drove a car onto a sidewalk and rammed pedestrians before stabbing people inside a shopping mall near Seohyeon Station in Bundang, Gyeonggi. The victims in both attacks were all random strangers to the assailants.

Police revealed the identities of both individuals because of the heinousness of their crimes.

The Seoul Central District Prosecutors’ Office on Friday indicted Jo, charging him with murder, attempted murder, theft and fraud.

Jo is accused of killing a 22-year-old man after stabbing him with a knife 18 times on a street near Sillim Station, as well as attempting to kill three other men all in their 30s. The prosecution said the crime is seen to be premeditated, as Jo reset his mobile phone and destroyed his computer prior to the attack in an apparent attempt to conceal evidence. He also is accused of stealing two knives in Geumcheon District to avoid leaving purchase records.

He is also accused of not paying the fare for his cab rides from Incheon to a location near Sillim Station.

Prosecutor said that Jo is seemingly addicted to video games and built up a sense of dissatisfaction and frustration from social and economic struggles. He is said to have targeted only young men, suffering from an inferiority complex against his peers, and attacked his victims in a manner mimicking a shooting game.

On the morning of the crime, Jo watched a video of a first-person shooter game. The prosecution said there was a parallel between his movement during the knife attack and that of the game characters.

He is also accused of anonymously posting derogatory comments on the Internet against a gaming YouTuber in December 2022.

Prosecutors on Friday also indicted 26-year-old Lee who posted an online murder threat that he would kill 20 women in Sillim-dong last month on charges of preparation for murder, intimidation and violation of the Information and Communications Network Act.

Lee is accused of purchasing a 32.5-centimeter knife after posting online that he will “kill 20 Korean women at Sillim Station on July 24.

Prosecutors through their investigation found that Lee posted about 1,700 misogynistic posts using the expression, “hannyeo,” a derogatory one used to describe Korean women in certain anti-feminist communities, for about five months from March.

BY SARAH KIM [kim.sarah@joongang.co.kr]