3. Defence

Complete story — includes the ending

An employee who works at a vintage clothes shop returns from lunch, and finds two workers and a customer dead. He quickly calls 999 and Devlin and Brooks investigate the victims, who were apparently killed with a sword or long knife. The medical evidence later indicates that the weapon was a bayonet. A fourth surviving victim soon points the detectives in the right direction – a man who was seen nearby just before the attack. He is eventually identified as John "Zero" Smith ( Rupert Graves ), an educated but homeless ex-military man, who is arrested with the weapon on him. Smith, who hasn't taken his medication for several months was previously charged with stalking a young woman but sloppy prosecution led to the case's collapse. It is also revealed that Smith is a law graduate, who has several law degrees. Smith has a long history of mental illness and occasional violent behavior but as long as he remains on his medication, he's practically a different person and there's a high degree of normality about him. He soon decides to defend himself at his trial. He proves to be a formidable opponent against Steel, and trying to avoid both hospitalization and jail, argues that he is not a danger to society so long as he is medicated and claims that he was not himself that day and therefore not the killer, while Steel attempts to prove that Smith is likely to stop taking his medications yet again. Steel brings in Smith's sister, Patricia ( Amanda Root ), and attempts to use Smith's paranoia to get his conviction. Signs of disociative identity disorder seem present throughout.