Seoul, Aug 11 : About 120 people have been apprehended across South Korea for posting murder threats on various online sites following the recent back-to-back fatal stabbing attacks in the Seoul metropolitan area, the Korean National Police Agency (KNPA) said on Friday. The KNPA said it has detected 315 online murder threats and nabbed 119 suspects on charges of writing those threats as of 9 a.m. Friday, reports Yonhap News agency. Online murder threats began to surface after a 33-year-old man wielding a knife killed one person and injured three others near a subway station in Seoul on July 21 and spiked after another man killed one and wounded 13 others in a rampage at a department store in Seongnam, south of Seoul, on August 3. The police agency said the number of online murder threats and relevant detainees surged by 121 and 52, respectively, from Monday, noting teens accounted for 34, or 52.3 per cent, of 65 people apprehended so far. The police and the prosecution said they are determined to seek stern punishment for those caught writing online murder threats in consideration of growing public fears. The prosecution has so far put 12 murder threat suspects under formal arrest. /IANS