Unknown creature was found by soldiers

This creature was found by Russian soldiers on Sakhalin shoreline. Sakhalin area is situated near to Japan, it’s the most eastern part of Russia, almost 5000 miles to East from Moscow (Russia is huge). People don’t know who is it. According to the bones and teeth - it is not a fish. According to its skeleton - it’s not a crocodile or alligator. It has a skin with hair or fur. It has been said that it was taken by Russian special services for in-depth studies, and we are lucky that people who encountered it first made those photos before it was brought away.