The recent online threat of a mass stabbing at a K-pop group’s concert turned out to be a prank by an 11-year-old girl, local police said Friday.

The child, whose identity has been withheld, posted an online threat Tuesday that claimed that she would stab fans gathered at a concert held at the Gocheok Sky Dome in western Seoul. Seoul Guro Police Station dispatched 39 officials to conduct an extensive search of the venue until after the concert was over at midnight that day.

Officials tracked down the 11-year-old via her IP address.

She told police that the online threat was a “joke because she was angry the merchandise of the K-pop group was too expensive for her to buy.”

She will be tried by the Seoul Family Court which deals with underage crimes and family-related disputes. Being under the age of 14, the child is defined as a “criminal minor” by the South Korean law and is immune to criminal punishment but can be subject to protective detention.