DETROIT – Family and friends of 18-year old Casey Willis are uniting in grief, coming together to honor and remember the Wayne State student who was shot and killed Christmas Day. Family and friends met on Tuesday at University Preparatory Academy in Detroit -- where she attended -- to remember the life she lived. Every time you saw her, you felt positive energy coming from her,” said Jerry Lawrence with University Prep High School. “Casey was the best big sister ever,” said Willis’ younger sister, Carley Bush. I love you.”Willis was shot and killed on Cardoni Street on Detroit’s east side.