Oceanshaft

Spotted this insect in school today. My first thought was that it might be a wasp since it had caught another insect, but the shape seemed too longish for a wasp and a little searching cleared up the matter, identifying it as a species of robber fly. Even found the Japanese name シオヤアブ. Couldn't get too good a picture of it as it kept flying away when I got too close, so in the end I just turned up the zoom, stretched out my arms slowly and snapped.