New partner Sam Casey joins a grieving Ronnie to find out who shot Matt dead. Sam suspects an accomplice of the recently convicted Mark Ellis but the trail ultimately leads to Jamaal Clarkson,a youngster whose brother Kieran was murdered in 2003,though the police closed the case as a suicide. Jamaal believes they were not interested as Kieran was black and tells Ronnie he knows Ellis was the murderer. It was his intention to kill Ellis but,on discovering that he had been sentenced,shot Matt instead as an act of revenge against the apathetic police. Whilst Alesha and Jake prepare a case of murder against Jamaal,Doug Greer,his barrister argues that the boy is himself a victim,whose crime was motivated by desperation,not calculation.