A Mokpo Vessel Traffic Service(VTS) controller is under investigation for improper monitoring of the passenger ferry that ran aground on an uninhabited islet last week off the coast of Jangsan Island in the southwestern Jeolla county of Sinan.

The Mokpo Maritime Police said on Monday that the Coast Guard is looking into whether the controller in charge of monitoring the area where the Queen Jenuvia 2 ferry crashed on Wednesday failed to detect risks.

The investigation found that the controller had turned off the route-deviation alarm at the time of the accident.

The controller told the authorities the alarm had been disarmed because it was interfering with their duties.

The alarm, when on, would sound even when small fishing boats deviated from their routes, which hindered the controller’s work, the maritime police explained.

At the time of the incident, the controller said they were managing five-thousand vessels, and another large ship was already off course and under intense monitoring.

The Coast Guard, which is investigating the cause of the ferry's grounding, has not yet brought charges against the controller.

The Queen Jenuvia 2 departed for Mokpo on November 19, carrying 267 people, including 246 passengers, and ran aground on a rocky islet in waters off the southwest coast the same day, injuring 30.