bethany farrell , 23 , died during a scuba diving trip on february 17 , 2015 .
young backpacker was in blue pearl bay off queensland 's hayman island .
she was on a wings diving adventure charter boat for her first scuba dive .
friends have claimed that staff on the boat deleted the last photos of her .
her family believe the images may have helped explain what went wrong .
police investigation is still underway and a report will be sent to coroner .