S23·E77 Line of Fire (1)

A paranoid schizophrenic is the main suspect in the case of a prowler who attacked a woman and then stabbed Reg, who answered the call for help. When Callum and Grace indentify the prime suspect, Neil recognises the man as someone he arrested four years previously, and takes pity on him when it emerges he did not receive appropriate medical help at the time, and has since been victimised by neighbours on his estate.