CSI: Miami Season 5 Episode 24

Shelly Seaver is stabbed to death after a violent struggle and marked with a carved bloody Y, the MO of a Boston serial killer. A similar knife belongs to motor-rider Travis Peck, but it's the wrong size. Traces under Shelly's fingernails of a fish species common in Boston and scratches allow Horatio to find fisherman Lucas Wade, who even has the alleged 'criminal gen', an XYY chromosome. While Lucas is in custody, a new Y-carved victim is discovered by her brave young son Arthur, but soon found not quit identical, and traced to Lucas' logical accomplices. Meanwhile Ryan has a hard time with another part of his past, and Eric with jealousy when Calleigh dates a handsome lawyer. The Wade story proves more complicated...