An investigation is underway to figure out how $100,000 worth of drones ended up in the Swan River during Perth’s City of Lights event on Sunday night.

The drone show, held over the water at Elizabeth Quay, was made up of around 500 devices… however, during the show, thousands of spectators witnessed about 50 of them falling out of formation, straight into the drink.

Turns out it was not part of the show.

Drone Sky Shows managing director Joshua Van Ross said the drones – which cost $2000 each – malfunctioned and an investigation was now underway. It’s understood that GPS and wind interference could possibly be the cause.

“I did cry a little bit last night, I am trying not to think about it … but it was an expensive show for us,” Mr Van Ross told 9 News Perth.

“There would have been an exclusion zone well over 120 metres [between the drones and onlookers] so people were not put in danger.”