Bobby Brown's Sister -- OUR Family Didn't Take Bobbi Kristina Deathbed Pic

Leolah Brown is pointing a suspicious finger at Whitney Houston's family -- saying the Browns had absolutely nothing to do with the deathbed photo of Bobbi Kristina, and the real culprit still has access to her.

TMZ broke the story ... the entire Brown family, except Bobby, is banned from seeing BK -- and Bobby's sister is obviously pissed, saying ... the pic "was taken when NO other Brown was around her. My brothers KNOW this and we have already determined who we are sure it WAS NOT! And believe me-IT WAS NOT A BROWN"!

Leolah added ..."If it were up to me! The sick and sorry people that continue to have permission to see her even still to this day-they would be COMPLETELY cut out NEVER to lay eyes on her again!"

Her insinuation is pretty clear -- but as we reported ... our sources say the hospice security team had visual evidence incriminating a Brown family member.