A famous bridge goes mysteriously missing in this Russian town

There is some or the other strange incident happening in the world every day. While a lot of them go unreported, something recently happened in Russia that has baffled not only the nation, but even the people living across different continents.
It so happened that in Murmansk region in Russia, recently, a famous metal bridge located Umba River in the Arctic region has gone missing! The bridge was 75 feet long, and weighed more than 50 tonnes.

Although, it was initially believed that the bridge has broken down, and its debris were lying in the river, later the citizens realised that there are no debris of the broken bridge. Did the debris disappear?
According to the news reports, a thorough examination revealed that the bridge had not sunk into the river. The locals thought that the bridge was broken and stolen by the thieves because in 2018 a gang of thieves had tried stealing transmission towers in a town nearby. Also, ten years ago, the country police had caught hold of scrap metal thieves who had siphoned off a bridge weighing 200 tonnes.

Murmansk is a port city that is located on both slopes and banks of Kola Bay, an estuarine inlet of the Barents Sea.

Well, by the time the mystery of the stolen bridge is solved, any guesses what reason could be behind its strange disappearance? Was it stolen by metal thieves, did it disappear due to a natural calamity, or it vanished by supernatural intervention?