how to find owner? is it even possible?

Hello, friend of mine (estate agent) sent me an url to pdf stored on S3 asking if it's possible to find who owns that specific 'bucket' with pdf file long story short: they're selling property but people can find old pdf from different estate agent with outdated information and it's annoying, https://s3-eu-west-1.amazonaws.com/mediamaster-s3eu

many thanks for any help! J