Casey Peckams.
Casey Peckams is 10 year old girl who is sister of Jessica Peckams and was killed by Trixie Sango in the exact same way as Frank Nightingale's niece, Alice Nightingale. She resembles a young Joan Fowles and is possibly a relative. She tried to help Trixie but was betrayed because Trixie said she "Didn't need a little girl sidekick" and was bruttally murdered