Shetland delivers unexpected Line of Duty-style twist involving long-serving character

**Warning: Contains spoilers for Shetland season 10 episode 3.**

Just as the BBC has announced that Line of Duty is returning, another of the broadcaster's long-running crime dramas has teased a very troubling development that would feel right at home in Jed Mercurio's hit series.

In season 10 episode 3 of Shetland, the mystery of who killed social worker Eadie Tulloch rumbled on.

Her body was discovered in episode 1 by Colin, one of her neighbours, who was delivering some food items to her. Shortly after entering her home, with Eadie nowhere to be seen, he went out back, where he found her tied to a fence.

The forensics later revealed that she had been out in the elements for a couple of days at least.

But who was responsible for such cruelty?

As Tosh and Calder delved into the victim's life, the list of suspects only grew – from Eadie's neighbours to sisters Stevie and Amy Shannon, whose case Eadie had overseen when she was still a social worker. At the same time, numerous new questions emerged, not least: how did Eadie come to have £400,000 in her account?

Her estranged son Ed told Calder that he didn't know anything about the money, given that they didn't have a relationship anymore, with the detective suggesting that the cash could have been a motive.

But it was in the most recent episode when the picture became a little clearer – but no less concerning.

According to Sandy, who had been following that particular strand, the money didn't belong to Eadie, but her late husband Robert, who also happened to be a former police officer.

Over a 12-year period, he had made several large cash deposits into the account, which stopped when he retired. And with no other income streams between them – no assets or properties, only their salaries – all signs pointed towards one thing: corruption.

Was Robert using his position of power and trust to line his own pockets? And could that have had something to do with drug trafficking in Shetland and the surrounding areas, which has reared its head in season 10?

With two paper statements still missing, Sandy floated the possibility that there may be something on them which can explain the origins of the money. But he's going to have a hard time locating them, by the looks of things, because they're currently in none other than Billy's possession.

Lewis Howden's character has been part of Shetland from the very beginning and has never appeared to be anything other than a true professional and an all-round good bloke.

Yet, his sparkling reputation is now in jeopardy following Sandy's findings.

But why would Billy take that key evidence, which could exonerate Robert? Or, by stark contrast, prove utterly damning?

Read more:

• Shetland favourite Alison O'Donnell reveals "Dark Tosh" storyline — and her partner's nervous reaction
• Shetland's Alison O'Donnell reveals why she cried after watching first episode following Douglas Henshall's exit

When Billy first joined the force, Robert was his sergeant – and their working relationship soon grew into a friendship, with their wives also becoming colleagues and friends.

It was Eadie who first introduced Billy to Morag, and shortly before Robert died, he asked the couple to keep an eye on his wife. But since both of their deaths, uncomfortable truths have begun to surface – and the police may have just uncovered another one.

Why does Billy have those statements, which he concealed in a filing cabinet in his home in the final moments of the episode – and only after checking over his shoulder to ensure that Morag was none the wiser about his underhand behaviour?

Speaking ahead of season 10's arrival, Alison O'Donnell addressed how that storyline impacts Billy and Tosh's relationship specifically, reflecting on the origins of their dynamic.

"Tosh and Billy have been through so much together," she said. "The tenderness we saw between them during season 3 when Tosh was sexually assaulted has informed everything Lewis and I have done since.

"And to have that very special bond hanging in the balance is really hard for both of them. Tosh will find herself torn between loyalties and faced with an almost impossible choice."

So, it certainly doesn't look good for Shetland's long-serving sergeant, but is it all just a horrible misunderstanding, or is there something much more sinister at play?

Shetland season 10 airs on Wednesdays on BBC One and BBC iPlayer. Seasons 1-9 are available to stream on iPlayer now. Ann Cleeves's Shetland novels are available to buy.

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