Broadchurch series two: our burning questions – Is Lisa dead? And is Ricky Gillespie the murderer?

Was Lisa disposed of in Thorps Agriservice's furnace?

Mid-way through tonight's episode, Ellie said what we were all beginning to think: "Lisa killed Pippa by accident, got rid of the body, went on the run." It certainly seemed plausible, especially given the fact that the last signal picked up on Lisa's phone was in Portsmouth – 18 hours after her final call to her mother at 5:17pm, which places her on the coast the afternoon after her and Pippa's disappearance. Was she about to jump on a ferry for France (and a possible reunion with Lee Ashworth)?

The first rule of Broadchurch is not to trust the obvious and, sure enough, when Miller and Hardy paid a visit to the deserted Thorps Agriservices (the business behind the old vehicle check form Ellie uncovers), they stumble upon the smell of blood and... a furnace. "Do you still think Lisa Newbury's alive?" asked Alec, planting a particularly gruesome image in our minds as the credits rolled. Could the 19-year-old have met her end in such grisly fashion? Broadchurch has always been creepy and dark, but never so grotesque.

Was Lisa having an affair with her uncle Ricky?

The 'other Gillespie brother' had already been mentioned by Lee Ashworth in the stack of evidence he presented to Hardy on the Sandbrook case, but this week we learned that the familial bond between him and his daughter had soured: "Tricky relationship with her dad, still uses her mum's surname," Ricky informed Ellie when asked about his niece and babysitter. "Sometimes she'd stay over, other times I'd take her home." Not missing a trick, Miller replied, "Did you fancy her?" – a question he sharply brushed off. But doth Mr Gillespie protest to much? We already know Ricky liked to put it about, but was he capable of seducing his attractive young niece? Or did he drug her with rohypnol to put a stop to her protestations? And was their encounter discovered by Pippa who then had to be hushed for good? It paints Ricky Gillespie as incestuous, debased and murderous – but it's possible.

Is Maggie the love of Jocelyn's life?

Any readers of Erin Kelly's Broadchurch novel will know that Maggie Radcliffe is gay and lives with her partner, Lil, but she also shares a close friendship with Charlotte Rampling's prosecuting barrister Jocelyn Knight. The Broadchurch Echo editor is the only character privy to the lawyer's secret (although, by now, we've all guessed she's going blind), pays frequent visits to her hilltop abode, and played a major role in convincing her to take the Latimers' case.

But tonight's episode saw Alec question Jocelyn about her lonely existence – and, to our surprise, she decided to open up: "Things are complicated and I made them more so. It was at a point when I should have been strong and I wasn't and I missed the person I was supposed to be with." The identity of that "person" remains a mystery, but we've got our suspicions of the nature of Maggie and Jocelyn's relationship – is the journalist the one she's pining over?

Is Kate Gillespie a suspect?

Pippa's mother has always been the distraught parent of a murdered child, divorced from her philandering husband and desperately remaining in a family home in case her missing niece returns. She was an object of pity, for us and for Alec Hardy, but tonight's episode called her innocence into question. The first we heard of it was Miller and Hardy's suspect list. "Ashworth, Ricky, Claire and that stalker on the estate," listed Ellie, before Alec chipped in with "possibly Kate?" 'What?', we asked – the weepy-eyed mother rattling around her empty, creaking house, haunted by the memories of the family she lost? Surely not...

But fast-forward through an ad break and Hardy was quizzing Lee on Thorps Agriservices. Had he heard of it? "No, unless it's one of the businesses Kate did the books for," came the reply – yet another question mark over Mrs Gillespie's head. And then, the humdinger. "Did you ever sleep with Kate?" Lee's answer was no, but a flashback told a different story as the pair were pictured in a clinch (below) as Pippa called goodbye from downstairs. If you thought of Kate as the squeaky clean mother and wife, you – and we – assumed wrong.

Why doesn't Claire think Lee did it?

Claire is clearly still frightened of Lee – her nervous glances around her home as Hardy and Miller charged out the door told us as much – but she still maintains he didn't commit the Sandbrook murders, despite her own compelling evidence. According to Claire, she and Lee spent the night the girls disappeared apart, before reuniting for a drink – a drink she still maintains he spiked. When she came to, he was cleaning the bathroom, washing linen and hoovering floors. All the patterns of a panicking murderer, right? Except Claire didn't go to the police – "I didn't want to think it was possible" – and she still doesn't think he's behind the killings. Lee clearly has a hold over his wife (last week's episode made that all too clear), but something tells us that's not the reason she's continuing to maintain his innocence. Claire's still hiding something – is it the identity of the killer?

Broadchurch continues next Monday at 9:00pm on ITV