»(SkyBlock) Griefing, Stealing and quite Possibly Hacking

On the 06/12/15, at around 18:45 (UK Time), A player warped to our island and started stealing our items and destroying our places. That players name/IGN was Marko004.
One of my friends who was on the server at this time told me this so we can stop this guy from doing any more harm. He said this:
"well, I trusted him (he asked and I didn't know what I was doing) he ran around normally and took our hoppers (2) went in my room stole everything from my chest broke my windows took my bed.."
'Anything else?' I asked him
He responded with:
"he stole lukes bed,and stole the chest under the hoppers, broke my glass in the front of my house and he broke a lot of blocks!"
From what I could also see when I came on-line was him continuing the destruction of our island. We have lost mostly all of our good resources that we had spent a lot of time getting.
The reason I had also included hacking within this is the fact that he warped to our island and my friend jjed trusted him, but he did not have permissions to do this which leads me to believe he used hacking but I could be wrong and he could of told jjed a command to let him be trusted as jjed knows NOTHING of thse commands as he is a big newbie to Minecraft.
I do not have a screen shot of him doing it but I do have screen shots of the aftermath he left. I did not make screen shots of him when he was doing it as I was more focused on kicking him from our island before he did even more damage. If you want Eye Witness reports then speak to jjed or Lukedahnerd on the server who are semi-frequent on it and are my Island-collogues.
Also the torches show missing items.
I hope you can take care of this rogue player and I expect some compensation for his deeds.

 

@PapaBoom128