Police authorities on Thursday launched an investigation into the claim that there were still survivors inside the sunken ferry Sewol.

The claim was circulating through Kakao Talk, a local smart messenger service.

“We are trying to verify the truth of the message that there were still survivors in the ship calling for help,” a police officer in charge of cyberterrorism told reporters, declining to be named.

Police are not ruling out the possibility that the message could be a prank. They said that it would sternly deal with any bogus message that would further hurt the families anxiously waiting for the return of their loved ones.

Earlier in the day, an elementary school student was caught sending a false message that young boys and girls were crying within the sunken ship. Observers said people might have churned out similar messages based on this false message.

There was also a video clip spreading on the Internet, in which a person claiming to be a survivor said he was still in a game room of the ship. But the police later found that the claim was falsified.

By Song Sang-ho (sshluck@heraldcorp.com)