Bugging a Raid instance ID

Currently there is someone that are bugging our DS raid...
if you share an ID with a raid group but you are not in that raid group,
you can somehow go inside the DS, even if you are not in that raid group and made the people that are already inside to be bugged out and DC

25 people already inside the DS, but then this asshat somehow can enter and because you can't have more than 25 people inside DS EVERYONE in our Raid Group got DC

I know how it's done, but i won't tell how in here

We figured out who doing this, but i don't know how to report him/her because it's hard to get a good evidence
For now we will mass report him via in-game report by right clicking his name and reporting for Cheating, i don't know if this even work

can you guys focus on fixing this? it's already an hour already for pete sake...

some Potential suspect, they are in Tanaris when we are inside, it's been ~30 minute and they are still in Tanaris, the SS is Before and After they Bug our Raid
http://i.imgur.com/LYyf2pt.jpg
http://i.imgur.com/12IV9HP.jpg