A police spokesman says the investigation into Sunday's helicopter crash near Rotterdam could take weeks. The aviation police are currently drawing up a plan for the investigation.

Four people were killed and one badly injured when a helicopter photographing the Tour de Port amateur cycling race suddenly swerved, started to spin and crashed to earth.

The Tour de Port was organised by the Port Authority as part of the celebrations of the fact that this year's Tour De France starts in Rotterdam.

The manufacturer's technicians will inspect the helicopter engine and a post-mortem will be carried out on the pilot. The results of the investigation will be sent to the Public Prosecutor's Office.

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