Police have apprehended 192 people for posting online threats of copycat crimes since a fatal stabbing incident in Seoul one month ago, officials said Monday.

During the month since the incident on July 21, in which a man wielding a knife killed one person and injured three others near Sillim Station, 431 online murder threats have been detected, according to the National Office of Investigation.

Police have nabbed 192 suspects responsible for the posts and formally arrested 20 of them.

Of the apprehended, 90 people, or 41.7 percent, were minors, including children under the age of 14 who are not subject to criminal prosecution, the office said.

Last Wednesday, an 11-year-old elementary school student was referred to the Seoul Family Court's juvenile division after posting a threat the day before to carry out a stabbing at a concert in Seoul.

Source: Yonhap News Agency