Luther and Ripley (Warren Brown) are called upon to investigate the deaths of two teenage gang members at the scene of a violent assault. Yet it is the attackers themselves who have been shot dead, rather than their intended victims, and when a third body is discovered shortly afterwards – that of a man involved in the death of a child – Luther realises a vigilante is on the loose.

With the killer using the internet to drum up support for his mission to correct the failings of the criminal justice system, Luther finds himself in a race against time to locate the next target – and in danger of putting the people he cares about most at risk.

Series 3 Episode 3 airs at 9pm on Tuesday 16 July on BBC One. To whet your appetite, here are ten teasing lines of dialogue from the ep…

» ‘Our boy’s killing predators, isn’t he?’

» ‘We’re the Filth.’

» ‘You’ve still got love in your voice.’

» ‘How much do you actually know about John Luther?’

» ‘You don’t want to read my mind right now – it’s full of scorpions.’

» ‘I’ve heard that one before: lack of conscience dressed up as philosophy.’

» ‘It’s time you were doing my job, having little Ripleys of your own.’

» ‘Do you understand social networking?’

» ‘Depravity is hardly in short supply in this city.’

» ‘This is the hardest thing I’ve ever had to ask someone to do.’

> Order Series 3 on DVD on Amazon.

> Buy the Series 1-2 boxset on Amazon.

What do you think of Series 3 so far? Let us know below…

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Watch the Series 3 trailer…