I don't know how I could've had better proof, he destroyed the base from out of my line of sight. He was the only one destroying my base for the entire time I was on the server and no one else was around. Its not even that he denied that he destroyed it either, he just thinks he is untouchable and won't be punished for it. I don't know if you can check the logs but I remember him saying something similar to, "Go ahead and use f1 I'll get out of it"

For reference, Xxredhurt and Windows ME both saw him destroy my base before these screenshots.