Police launched an investigation Saturday into allegations the Islamic State militant group hacked a South Korean firm's computer network to retrieve data on 20 South Koreans, officials said.

The company, which provides a news-clipping service, appears to have come under a hacking attack that led to a leak of the names and email addresses of 20 public officials and civilians, according to police and other intelligence officials.

Police secured traces of the hacking, including connection records left on the company's computer server, at the firm.

Those names and addresses appeared in a YouTube video the IS uploaded in February and later deleted, they said, adding that they were analyzing the video.

The 49-minute video contains a violent scene in which the IS group execute a hostage. In the video, the group also incited terror against those mentioned, according to the police.

Officials said they are looking into a possible link between the hacking and a video the IS posted in November in which it threatened to carry out terrorist attacks on hostile countries, displaying the flags of 60 nations, including that of South Korea. (Yonhap)