As Lochanfoy reels from the brutal murder of local piano tutor Niall – and from the discovery of a human heart on the beach – suspicion immediately falls on the only ex-offender in the community: Leighton Thomas. 

But in a preview clip for episode two, DS Annie Redford (Laura Fraser) is the only one willing to stick up for him.

Sure, from an outsider's perspective it looks pretty bad. Leighton (William Ash) murdered two men 20 years ago, lives alone, has no love life and a struggling business. DCI Lauren Quigley (Siobhan Finneran) is an outsider brought in from Glasgow to tackle the case, and that's certainly her line of thinking. 

But Annie's the copper with the local knowledge – and she's not one to be intimidated by her superiors. 

The tense episode will see the case get even more complex as clues come to light. Why did college principal Craig Petrie take the phone from Niall Swift's dead body? What's going on with Jonjo? And why did Dr Marr argue with Niall on the day of his death?

The Loch continues on Sunday 18th June at 9pm on ITV