(Portland, OR)  --  An investigation is under way after a two-year-old girl pricked her finger on a dirty needle on a MAX train.  Elizabeth and Brian Higby tell KATU-2 they were riding the MAX Green Line from Clackamas Town Center to Gateway Transit Center Tuesday when it happened.  Elizabeth says their daughter was sitting on her lap when she reached behind her and was pricked by an empty syringe tucked into a crevice between the seat and the shelf behind it.  Transit police are reviewing surveillance footage to find out who left the needle there.