An interloper is capable of viewing my secret facebook group?

[Jordan Lanham]

Ok, so there is this guy (I have a decent idea as to who he is, but we no longer talk since we go to different high schools and hardly even talked in middle school), but just trust me when I tell you it's him. Anyways, my class has a GT Chemistry facebook group and the interloper has created several different facebook accounts and tried to get accepted into the group. Anyways, we had to end up making the group secret (it was open before), but he is still sending us pictures of the new content on the group and bugging/spamming the people within the group. No, he is not a member- you can tell since in the pictures he can't comment, like, etc. Anyways, on my little brothers' facebook account I tried to look up the group and find it, but it did not show up. Does anybody know how the interloper can view the group content?

Any help is greatly appreciated!
~Jordan

[Matteo Ricci]

Maybe there's some inside help?

As in from one of your group members..